1. Bridge, Culvert, and Tunnel Design and Performance
2. Construction: General
3. Construction: Pavements
4. Construction: Structures
5. Facilities, Equipment Design, and Performance
6. Bituminous Materials
7. Cement and Concrete
8. Mineral Aggregates
9. Pavement Management and Rehabilitation
10. Safety
11. Soils, Geology and Foundations

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Abstract: Stress-laminated timber bridge decks have gained increasing popularity in the U.S. in recent years. As with all wood exposed to the environment, wood for these decks must be treated with preservatives. There has been reluctance to build Chromated Copper Arsenate (CCA) treated wood bridges due to concerns about dimensional stability. Because no research has been undertaken to investigate the use of CCA treated Southern Pine stress-laminated bridge decks, a good resource for economic rural bridges has remained untapped. The objective of this study was to evaluate the performance of various wood preservatives on stress-laminated Southern Pine bridge decks. A total of nine decks with seven different preservatives were built and exposed to the environment for over 2 years. Force levels in prestressing rods and wood moisture contents from each deck were continuously monitored. It was found that the short-term variations in the rod stress levels are less for decks with oil-type preservatives, as compared to CCA preservatives. The long term performance for decks with both preservative types was found to be similar. The anchorage effect on the deck performance was found to be negligible.

Nur Yazdani, Civil Engineering Department, Florida A&M University-Florida State University College of Engineering, 2525 Pottsdamer Road, Tallahassee, Florida 32310; Tel: 850-410-6125; Fax: 850-410-6142; Email: yazdani@eng.fsu.edu, Joy O. Kadnar, Gas Operations Division, City of Tallahassee, Tallahassee, Florida 32310; Jim Kainz, University of Colorado, Boulder Colorado; and Mike Ritter, USDA Forest Service, Forest Products Laboratory, Madison, WI 53706.

00-0389 "Asphalt Surfaces on Steel Bridges"

Abstract: A variety of materials have been used for wearing surfaces on steel bridge decks. This paper identifies the requirements for these paving materials, describes the various asphalt-based materials that have been used, provides a description of the construction process, and discusses the expected field performance and maintenance requirements for the most common materials used. The selection of the wearing surface should be based on life cycle costs, not just initial construction costs. Life cycle calculations must include consideration of initial construction costs, expected life, maintenance and rehabilitation costs, and user delays costs associated with the removal and replacement of failed surfaces. Reliability, durability, and skid resistance of the wearing surface is very important to prolong the life of the surfacing and minimize delays to users caused by frequent replacements. Summary: This paper has presented a brief overview of the following: 1) Requirements for wearing surfaces over steel decks, 2) Materials used in the wearing surfaces, 3) Typical construction practices for the different systems, 4) Expected performance and maintenance needs for the different systems. The selection of the system should be based on life cycle costs, including user delay costs, not initial construction costs. Life cycle calculations must include consideration of the following: 1) initial construction costs, 2) expected life, 3) future maintenance and rehabilitation costs, 4) user delay costs associated with removal and replacement of failed surfaces. Reliability, durability, and skid resistance of the wearing surface is very important to prolong the life of the surfacing and to minimize delays to users caused by frequent replacements.

R. Gary Hicks, Ian J. Dussek, and Charles Seim, Oregon State University, Department of Civil Engineering, Corvallis, OR 97331, Tel: 541-737-5318, Fax: 541-737-3052, Email R.G.Hicks@orst.edu.

00-0414 "Asphalt Plug Joints: Refined Material Tests and Design Guidelines"

Abstract: Highway builders and rehabilitators throughout the United States use asphalt plug joints (APJs) in bridge expansion joints following manufacturers recommendations. The joint performance varies widely as indicated in recent surveys. State departments of transportation are installing joints in unsuitable sites and/or are overlooking other sites where APJs may work well. To aid bridge engineers this study has developed rational design guidelines for APJs. The research suggests suitable applications, materials characterization, design guidelines, and validation procedures. Two critical material properties are required to qualify APJ material: relaxation and glass transition temperature. Both properties may be obtained using a slight modification of the standard TSRST asphalt test. This modified standard test was conducted and compared with the near-full-scale test results. Design guidelines are based on field observations, material tests, near full-scale testing, analytical evaluations, and a survey of DOT experience. Design recommendations are provided and joint design changes are proposed to help mitigate the present shortcomings.

Brian K. Bramel, National Association of Homebuilders; Charles W. Dolan, Jay A. Puckett, and Khaled Ksaibati, University of Wyoming, Dept. of Civil & Architectural Engineering, P.O. Box 3295, Laramie, WY 82071-3295, Tel: 307-766-2857, Fax: 307-766-4444, Email: cdolan@uwyo.edu.

00-0488"The Adverse Effect of AASHTO'S LRFD Criteria for Deflections on the Integrity and Durability of Reinforced Concrete Deck Slabs"

Abstract: This paper briefly examines the new deflection criteria of the LRFD Bridge Design Specifications for deck-type highway bridges. This examination suggests that abandonment of superstructure deflection limitations, as the new provisions explicitly "encourage", and omissions of permanent mid-span braces, as the new provisions appear to encourage, will have adverse effects on the long-term integrity and durability of reinforced concrete deck slabs to the extent that deck slab replacement intervals may become considerably less than 250,000 hours. This is the present age by which many deck slabs will have deteriorated and disintegrated to such an extent that they have become hazards to the movement of vehicular traffic. As documented in this paper, excessive flexibility has tentatively been identified as one of the unfavorable characteristics of bridge superstructures with premature concrete deck slab disintegration. If present flexibility is as detrimental to the durability of deck slabs as many contend, then significantly increased flexibility could have incalculable long-term adverse consequences. To avoid such consequences, this paper urges that historic flexibility limitations be retained until long-term superstructure flexibility research on aging concrete deck slabs is accomplished. Then, specification changes and future bridge characteristics can be based on known consequences. Otherwise, unwary transportation administrators who adopt LRFD recommendations and abandon live-load deflection limitations may eventually find themselves owners of defective bridges that may have to be replaced rather than just being re-decked.

Martin P. Burke, Jr., PE, Burgess & Niple, Limited, 5085 Reed Road, Columbus, OH 43220, Tel: 614-459-2050, Fax: 614-451-1385, Email: mburke@burnip.com.

00-0654 "Field Performance of an Integral Abutment Bridge"

Abstract: The behavior of an integral abutment bridge near Rochester, Minnesota was investigated from the beginning of construction through several years of service by monitoring over 180 instruments that were installed in the bridge during construction. The instrumentation was used to measure abutment horizontal movement, abutment rotation, abutment pile strains, earth pressure behind abutments, pier pile strains, prestressed girder strains, concrete deck strains, thermal gradients, steel reinforcement strains, girder displacements, approach panel settlement, frost depth, and weather. In addition to determining the seasonal and daily trends of bridge behavior, live load tests were conducted. All of the bridge components performed within the design parameters. Effects from the environmental loading of solar radiation and changing ambient temperature were found to be as large or larger than live load. The abutment was found to accommodate superstructure expansion and contraction through horizontal translation rather than rotation. The abutment piles appeared to be deforming in double curvature, with measured pile strains on the approach panel side of the piles indicating the onset of yielding.

Andrew Lawver, Minnesota Department of Transportation, Email: lawv001@tc.umn.edu;

Catherine French and Carol Shield, Department of Civil Engineering, University of Minnesota, 500 Pillsbury Drive S.E., Minneapolis, MN 55455-0116, Tel: 612-625-5522, Fax: 612-626-7750; Email: cfrench@tc.umn.edu or ckshield@tc.umn.edu.

00-1057 "Landmark American Bridges of the 21st Century"

Abstract: The paper will address the qualities a bridge must have in order to become a landmark capable of benefiting cities from an urban design point of view. In addition to functionality and serviceability, a landmark bridge should have other qualities. Among them uniqueness and technical achievement, contextual integration and architectural appropriateness and finally artistic structural shaping and a clean geometry are essential. The paper will also help raise awareness of the need for excellence in bridge design by illustrating how bridges can play a symbolic role as civic infrastructure. Many communities across the US have become very interested in the appearance of their bridges and the paper will document the results of some of these efforts. The paper will use, as a reference, a group of new major bridges currently under construction, or in the final design phases. These bridges will become the new defining landmarks of some of the most important urban centers in the United States and will be located in cities like Boston, Washington, D.C., San Francisco, Chicago, Des Moines, Buffalo and Clearwater in Florida. Conclusions: Landmark bridges like the Brooklyn Bridge in New York City and the Golden Gate in San Francisco are the symbols of the cities where they are located. After the year 2000, several new bridges will be built in similar urban centers. The paper concludes that the qualities needed to achieve landmark status have been achieved by several of these bridges currently in the final design or construction. These qualities will be illustrated and explained in the paper through the documentation of different urban bridges.

Miguel Rosales, Rosales Gottemoeller & Associates, Inc., 305 Newbury St. #21, Boston, MA 02115, Tel: 617-247-7499, Fax: 617-247-7139, Email: mrosales@rgabridges.com.

00-1191 "Field Performance of Stress-laminated Timber Bridges"

Abstract: Stress-laminated timber bridges were introduced into the US in the late 1980's. Since that time, over 500 stress-laminated bridges have been constructed throughout the U.S. To evaluate their performance, the Forest Service and the Federal Highway Administration initiated a nationwide bridge monitoring program. This paper presents field evaluation and monitoring results obtained for these bridges which have been continuously monitored for two or more years after installation. Based on the monitoring program, performance of stress-laminated timber bridges is generally satisfactory, although there are several areas where observed performance can be improved. Conclusion: A summary of key recommendations follow. 1. When bridges are stressed with a single jack, 3-6 stressing passes should be made along the bridge length to insure uniform prestress. 2. Attachments to the bridge superstructure should not be made until after the bridge has been fully stressed two times. 3. The average moisture content of the wood laminations at the time of bridge construction should preferably be 10-16 percent but should not exceed 20 percent. 4. For bridges constructed of sawn lumber, bar force should be checked at annual intervals for the first two years after construction, and every two years thereafter. For bridges constructed of glued laminated timber, bar force should be checked every 2 years for the first 4 years after construction and every 5 years thereafter. 5. Bridge live load deflection should be limited to L/500. 6. When oil-type wood preservatives are used, the preservative retention should not exceed that recommended in AWPA Standard C14 (29). 7. Consideration should be given to enclosing stressing bars in grease-filled plastic tubes if the bridge is subjected to corrosive de-icing chemicals or if the lumber laminations are treated with waterborne preservatives containing copper and it is anticipated that the lamination moisture content will exceed 20 percent.

Michael A. Ritter, James P. Wacker, Forest Products Laboratory, One Gifford Pinchot Drive, Madison, WI 53705-2398, Tel:608-231-9229, Fax: 608-231-9303; Email: mritter@facstaff.wisc.edu, jpwacker@facstaff.wisc.edu; Sheila Rimal Duwadi, Federal Highway Administration, 6300 Georgetown Pike, McLean, VA 22101, Tel: 202-493-3038, Fax: 202-493-3442, Email: sheila.duwadi@fhwa.dot.gov.

00-1231 "The Seismic Performance of Timber Bridges"

Abstract: When compared to concrete and steel highway bridges, the seismic performance of timber bridges is not well understood. This is due, in large part, to the fact that little effort has been spent on documenting the seismic performance of timber bridges in past earthquakes, or conducting research to develop an improved understanding of the seismic design and/or retrofit requirements for such bridges. This paper presents the preliminary findings of a study conducted at the Multidisciplinary Center for Earthquake Engineering Research and the University at Buffalo, which was sponsored by the Federal Highway Administration. The paper presents a summary of the seismic performance of timber bridges in past earthquakes, results of an experimental and analytical assessment of the strength and ductility capability of timber pile substructures, and the results of work conducted to assess the seismic vulnerability of timber bridges (principally shaken in the longitudinal direction) and document the expected modes of failure. Study conclusions included the following: (1) Timber bridges are fairly robust under earthquake-induced shaking, but are not immune to damage or collapse, especially when strong ground shaking is coupled with soft soils; (2) performance in the transverse direction is generally acceptable; the primary vulnerabilities are in the longitudinal direction; (3) the extent of historic and predicted damage can be related to deck type (timber or concrete), pile condition, available seat width, and connection details at the pier cap and cross-bracing; (4) simple retrofits can be provided for inadequate seat widths and connection details; and (5) simple design provisions (response modification factors) can be developed for AASHTO bridge specifications.

John B. Mander, University at Buffalo, 230 Ketter Hall, Buffalo, New York 14260, Tel: 716-645-2114 ext. 2418, Fax: 716-645-3733, Email: jmander@acsu.buffalo.edu; Dion Allicock; and Ian M. Friedland, P.E., Applied Technology Council, 1300 Pennsylvania Avenue NW, Suite 700, Washington, DC 20004, Tel: 202-204-3011, Fax: 202-204-3012, Email: ifriedland@atcouncil.org.

00-0136 "High Performance Steel Bridge Design and Cost Comparisons"

Abstract: High Performance Steel (HPS) is a relatively new and promising material for steel girder bridges. Several studies have been conducted regarding high performance steel, its properties, and its potential future use. The many benefits of HPS include increased strength, lighter structures, possibly less expensive bridges, ease of fabrication due to better weldability, and significantly greater ductility and toughness than conventional steels of similar strength. Several bridges that have been completed using HPS are now in service and have met or exceeded expectations. This paper presents the designs and cost comparisons for six alternative designs for a two-span steel girder bridge. The design alternatives include three homogeneous HPS 485W (HPS 70W) girders, two conventional 345W (50W) girders and a hybrid 345W/HPS 485W (50W/HPS 70W) girder. The results show that, although the homogeneous HPS girder designs reduce the steel weight significantly, the additional costs of the HPS material tends to outweigh the benefits of the reduced steel weight. However, the hybrid design demonstrates considerable and definite savings in both steel weight and total costs. The hybrid design demonstrates the greatest savings over conventional steel bridges. The 7 girder hybrid bridge compared to the original 9 girder conventional steel bridge showed a weight savings of 15.3% and a erected cost savings of 18.6%. Comparing the hybrid design to a 7 girder conventional steel bridge, the weight savings is 10.9% with a cost savings of 11%. These were computed using current material costs for the HPS material. As HPS becomes commonplace, the price will drop. The paper also assumes a practical projected cost for HPS material and recomputes the cost savings. For the two cases above, the cost savings increase to 21.9% and 14.6%, respectively.

Michael G. Barker, University of Missouri-Columbia, E2509 EBE, Columbia, MO 65211, Tel: 573-882-2467, Fax: 573-882-4784, Email: barkerm@missouri.edu and Steven D. Schrage, BSI Constructors.

00-0153 "The Adverse Effect of AASHTO'S LRFD Specifications for Transverse Braces on the Integrity and Durability of Reinforced Concrete Deck Slabs"

Abstract: This paper briefly examines transverse bracing provisions of the LRFD Bridge Design Specifications for deck-type highway bridges. This examination suggests that implementation of these provisions will not only have an adverse affect on the integrity and durability of reinforced concrete deck slabs, and consequently on life-cycle bridge costs, such implementation also has the potential for adversely affecting the desirability of steel bridge construction. Rather than avoiding use of mid-span braces as implied by LRFD provisions, this paper urges that mid-span braces be more generally recognized as primary elements of complex superstructure structural systems and as such be sized and spaced to function not only as transverse flange braces for dead, live and contingency loadings, but also integrally with concrete deck slabs to laterally distribute vehicular loads. The primary thrust of this paper is that radical changes in bridge superstructure structural system characteristics should not be permitted or encouraged unless and until definitive long-term research on the effects that such changes will have on serviceability and durability are known and especially the effects of elevated stresses on the durability of reinforced concrete deck slabs. Otherwise, unwary transportation administrators may find themselves with numerous bridges with rapidly deteriorating deck slabs, fatigue distressed braces, and superstructures highly vulnerable to unanticipated construction, service and maintenance related contingencies.

Martin P. Burke, Jr., PE, Burgess & Niple, Limited, 5085 Reed Road, Columbus, OH 43220, Tel: 614-459-2050, Fax: 614-451-1385, Email: mburke@burnip.com.

00-0175 "Innovative Prestressed Concrete Bridge Deck Panel Systems"

Abstract: This paper presents the latest innovation in precast prestressed bridge deck panel systems. Two types of prefabricated deck systems have been developed at the University of Nebraska-Lincoln under the National Cooperative Highway Research Program (NCHRP) Project No. 12-41. The first system is a full-depth precast, prestressed concrete bridge deck panel, which is transversely pretensioned and longitudinally post-tensioned. The new system is shown to have better crack control, to be 10 percent thinner and 20 percent lighter in weight than solid conventional reinforced concrete decks. Also, testing showed that the new system has almost double the flexural capacity required by the American Association of State Highway Transportation Officials (AASHTO) Standard Specifications. This system has high construction speed with minimal interruption to the traffic. The second system is a continuous stay-in-place (SIP) precast, prestressed concrete panel with cast-in-place (CIP) topping called the NUDECK. The SIP panel serves as permanent formwork and houses the positive moment reinforcement. The precast panel covers the entire width of a bridge resulting in elimination of field forming of overhangs and reduction of the time and labor required for installing a larger number of individual panels between girder lines. The proposed panel is unique in that it is continuous transversely and longitudinally, and it utilizes reinforcing bars without concrete to preserve the strand prestress across girder lines. No proprietary materials are used in producing the panels.

Maher K. Tadros, Ph.D., PE, University of Nebraska, USA, 6001 Dodge St., Omaha, NE 68182-0178, Tel: 402-554-2985, Fax: 402-554-3288, mtadros@unomaha.edu; Sameh S. Badie, Ph.D., PE, University of Nebraska, USA, 6001 Dodge St., Omaha, NE 68182-0178, Tel: 402-554-3286, Fax: 402-554-3288, badies@unomaha.edu; Mantu C. Baishya, Ph.D., PE, Senior Design Engineer, Tadros Associates, LLT, 14707 California St., Omaha, NE 68154-1900, Tel: 402-341-0640, Fax: 402-431-0160, mbaishya@unomaha.edu; and Takashi Yamane, PE, Chief Engineer, Kyokuto Corporation, Towaedogawabashi Building, 347 Yamabuki-cho Shinjuku-ku, Tokyo 162 Japan, Tel: 03-3269-4623.

00-0176 "Long-Term Performance Evaluation of Bridges Constructed with Composite Prestressed Concrete Panels"

Abstract: This paper summarizes the results from a research project that evaluated the long-term performance of bridges constructed with composite prestressed concrete panels. The particular construction system investigated utilized full-span prestressed concrete panels that would be typical for bridges with spans of 40 ft (12 m) or less. A full-scale bridge specimen was constructed and subjected to 5 million cycles of service loading and 48 weeks of durability exposure cycling. This was done in order to assess the potential for delamination as well as the resistance to chloride-induced reinforcement corrosion. The exposure cycling greatly accelerated the penetration of chlorides, producing concentrations in the deck that exceeded those from bridges which had been in service for nearly 40 years. The results from this study showed that long-term composite behavior can be achieved in these structures by applying a raked finish to the top surface of the prestressed panels. Corrosion measurements (as well as visual inspection of the reinforcement at the end of the test program) revealed the need to modify the current continuity connection (for positive moment) at interior piers in order to provide a more durable structure. The detail of bending strands upwards should not be used with shallow-depth structures, in which the bent-up strands may extend close to the deck surface.

Robert J. Peterman, Assistant Professor, Kansas State University Department of Civil Engineering, 119 Seaton Hall Manhattan, KS 66506, Tel: 785-532-7612, Fax: 785-532-7717, Email: bob@ksu.edu; and Julio A Ramirez, Professor and Assistant Head for Graduate Studies, Purdue University Department of Civil Engineering, 1184 Civil Engineering Building West Lafayette, IN 46907, Tel: 765-494-2716, Fax: 765-496-1105, Email: ramirez@ecn.purdue.edu.

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2. Construction: General

00-0110 "Quantified Checklists for Construction Inspection Examination"

Abstract: This paper shares practical experience about how to salvage and use much of the valuable information gathered by inspectors. It specifically explains how to develop checklists, which use attributes to classify events as pass/fail or conforming/nonconforming. The checklist approach converts this qualitative information into quantitative data, which can be used to improve specifications and manage quality processes. Although much attention has been focused by the transportation industry on managing and quantifying materials, the vast majority of characteristics cover workmanship. While materials are usually tested, workmanship is usually "examined". Because examination is done visually, and without apparatus, it is relatively efficient because many characteristics can be quickly inspected. The refinement of examination techniques is essential for the full implementation of the incentive/disincentive approach to contractor payments. Stated briefly, checklists are developed by selecting important attributes from program standards such as specifications, drawings, or manufacturer's information. Inspectors examine each attribute, and mark it as either conforming (yes), nonconforming (no) or not applicable (NA). The "percent conforming" with requirements is determined by dividing the number of conforming events by the total events inspected and converting the ratio to percent. The process is being computerized, which will also allow individual attributes to be quantified, tracked and analyzed. The Construction Operations Section of the Arizona Department of Transportation (ADOT) is using the results to analyze specification effectiveness, and manage inspection and quality processes. The checklists are also being used by ADOT field offices to award incentive payments for quality workmanship on design-build projects.

Allan F. Samuels, Construction Operations Section, 206 S.17th Ave, MD 134A, Phoenix, AZ 85007, Tel: 602-712-8940, Fax: 602-254-5128, Email: asamuels@dot.state.az.us.

00-1192 "Kentucky Contract Time Determination System"

Abstract: This paper reports on the results of research for the Kentucky Transportation Cabinet (KyTC) to develop a new method for determining construction contract time for its highway construction contracts. The current system in Kentucky was analyzed to determine how a new system could provide better-estimated durations. Other DOT's current methods were analyzed to provide insight into a new system. It was pre-determined that a computer system was best suited; however, the development of the system needed input from KyTC engineers with construction experience. A task force of the study advisory committee worked with Kentucky Transportation Center research engineers to develop the new contract time determination system, KY-CTDS. The KY-CTDS program was developed as a conceptual estimating tool for predicting KyTC construction contract time. It makes use of pre-determined project classifications with major activities listed that are believed to control the project schedule. Production rates and activity relationships have also been determined and are imbedded in the program. Final adjustments can be made by experienced KyTC engineers using the model. The program utilizes Microsoft Project® 98 and Microsoft Excel® Version 7.0 software and operates on a personal computer. It outputs a graphical bar chart schedule to only be used in estimating contract time for bidding purposes. Program output should also help in resolving construction disputes. The program is not suitable for detailed scheduling of construction operations.

Donn E. Hancher and Ray Werkmeister, Civil Engineering Dept, University of Kentucky, Lexington, KY 40506-0281, Tel: 606-257-4857, Fax: 606-257-4404,

Email: hancher@engr.uky.edu.

00-1472 "A Method to Determine Minimum Contract Time for Highway Projects"

Abstract: The A+B bidding concept is designed to shorten the total contract time by allowing each contractor to bid the number of days in which the work can be accomplished, in addition to the traditional cost bid. The SHA is then presented with the problem of determining a reasonable range of contract time submitted by the bidders. Most SHAs do not currently restrict the range of the time bid (B). However, there are several problems that may arise from an unrestricted range of B. First, if there is no minimum set for B, a bidder may inflate the cost bid and submit an unreasonably low B, using the excess cost bid to cover the disincentives charged for exceeding the time bid. Second, if there is no maximum set for B, then a bidder with a high B and a low cost bid may be awarded the job and make an unreasonable amount of money from incentive payments. This study develops a quantified model of the price-time bidding contract. Conclusion: This research offers a quantifying model to determine a reasonable minimum limit of contract time for SHAs and uses projects from the Florida DOT to illustrate this model. This model framework can be adopted by any agency that plans to use A + B method, but the formula of construction cost as a function of duration needs to be created by the agency depending on construction type, location, and economic factors.

Jin-Fang Shr, Benjamin P. Thompson, Jeffrey S. Russell, and Bin Ran, University of Wisconsin – Madison, Department of Civil and Environmental Engineering, Room 2304, 1415 Engineering Dr., Madison, WI 53706, Tel: 608-262-7244, Fax: 608-265-9860, russell@engr.wisc.edu.

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3. Construction: Pavements

00-0974 "Top-Down Cracking of Rigid Pavements Constructed with Fast Setting Hydraulic Cement Concrete"

Abstract: Jointed Plain Concrete Pavement (JPCP) test sections were constructed using Fast Setting Hydraulic Cement Concrete (FSHCC) as part of the California accelerated pavement testing program (CAL/APT). Many of the longer slabs cracked under environmental influences before any traffic load was applied to them. Data from field instrumentation was recorded and analyzed along with laboratory test data to determine the cause of the cracking. Cores drilled through the cracks indicated that cracking initiated at the top of the slabs and propagated downwards. This was confirmed using the ILLI-SLAB (ILSL2) finite element package where high tensile stresses were predicted at the top of the slab as a result of the differential drying shrinkage between the top and base of the slab and the non-linear nature of the negative temperature gradients through the slab. Laboratory free shrinkage tests on the test section concrete indicated significantly higher shrinkage than an ordinary Type II portland cement. Load plus environmental stress analysis with ILSL2 suggested the critical failure location for the FSHCC pavements would be near the corner of the slab not at the mid-slab edge. Conclusions: The use of high shrinkage hydraulic cements in rigid pavement construction should be discouraged as these can result in high differential shrinkage gradients and premature failure. Fast setting hydraulic cements to not necessarily have high shrinkage and some can have significantly lower shrinkage than typical Type II cements. Shorter slab lengths will reduce tensile stresses and thereby reduce the chance of premature failure.

Andrew Heath, Transportek, CSIR, PO Box 1619, El Cerrito, CA, 94530. Tel: 510-231-5629, Fax: 510-231-9553, Email: aheath@csir.co.za; and Jeffery Roesler, University of California at Berkeley, Pavement Research Center, 1353 S. 46th St, Bldg 480, Richmond, CA, 94804-4603. Tel: 510-231-5746, Fax: 510-231-9589, Email: jroesler@uclink4.berkeley.edu.

00-1183 "Construction Productivity and Constraints for Concrete Pavement Rehabilitation in Urban Corridors"

Abstract: One objective of the Caltrans’ Long Life Pavement Rehabilitation Strategies (LLPRS) is to have a construction production of 6 lane-kilometers within a 55-hour weekend closure. A constructability analysis tool was developed to help Caltrans determine which rehabilitation and construction strategies were the most feasible in an urban environment to maximize production and minimize traffic delay. With the assistance of California concrete paving contractors, the constructability analysis explored the effects of the following parameters on the construction production of concrete pavement rehabilitation in California: pavement thickness, concrete material, curing time, number and capacity of resources, number of lanes to pave, type of construction scheduling, and alternative lane closure strategies. Conclusions: The constructability analyses indicated the proposed strategy to rebuild 6 lane-kilometer within a 55-hour weekend closure had a low probability of success. The most optimistic target is to rebuild 4 lane-km, assuming no access and mobilization problems. The analyses showed concrete curing time was not the most critical activity for the overall production. The analysis showed less than 20 percent production capability is lost when curing time was changed from 4 hours to 12 hours. Material delivery resources, especially dump trucks for demolition and end dump trucks for concrete supply, were the major constraints limiting the production. The new slab thickness proved to be a major element influencing the production capability. Increasing the concrete slab thickness from 203 to 305mm reduced the production by about 50 percent. A concurrent working method, where demolition and paving activities proceed simultaneously, was more productive than a sequential working method in which paving commenced only after demolition was finished. The number of lanes to be paved impacted the production capability. When comparing various construction windows, like continuous closures and weekend closures, continuous closures were more productive and less inconvenient to the public.

Eul-Bum Lee, C. William Ibbs, Jeffery R. Roesler, and John Harvey, University of California at Berkeley, Department of Civil and Environmental Engineering, Construction Engineering and Management, 215 McLaughlin Hall University of California, Berkeley, CA 94720, Tel: 510-642-0735, Fax: 510-643-8919, Email: eblee@uclink4.berkeley.edu.

00-1198 "Factors Affecting Overlay Ride Quality"

Abstract: This study was conducted to identify the predominant factors affecting the achievable smoothness of asphalt overlays. It approaches the subject from the perspective of a contracting entity (state highway agency). The basis of the study is a roughness survey incorporating 4,270 lane-km (2,650 lane-mi) and two full construction seasons of hot-mix asphalt concrete (HMAC) paving. Among the notable findings relating to achievable ride quality are the identified associations with functional classification (highway system), original surface roughness, and the use of a special provision for smoothness. Issues that were not found to relate significantly to achieved smoothness include surface mix type, the use of additional structural layers, the use of milling, and time-of-day restrictions on construction activities (i.e., night paving).

Kevin McGhee, Virginia Transportation Research Council, 530 Edgemont Road, Charlottesville, VA 22903, Tel: 804-293-1956, Fax: 804-293-1990, Email: McGheeKK@vdot.state.va.us.

00-1452 "Effect of Lime on Ignition Furnace Calibration"

Abstract: This study investigated mix components, other than aggregate source, that were perceived to affect the ignition furnace mixture calibration. Four sets of experiments using one aggregate type were designed and run to evaluate the impact of lime content, sulfur content, calcium carboxylates, and fines. Four asphalt binders, representing high and low sulfur contents, were evaluated in this study. The concentration of hydrated lime added to the mixtures was varied from 0 percent to 2 percent by weight and was found to have a significant effect on the ignition furnace correction factor for all four binders. The magnitude of the effect was large enough to cause the quality control tests to fail the tolerances established by the Virginia Department of Transportation. The lime appears to react with SO₂ formed from the combustion of organic sulfur to generate calcium sulfate. The amount of sulfur present in the asphalt significantly affects the ignition furnace correction factor, but to a lesser degree than the lime content. Consequently, some calcium carbonate is presumed to have formed from the reaction with CO_2. Calcium salts, basalt fines, and portland cement did not have a significant effect on the ignition furnace correction factor. Additional testing should be conducted to assess the effect of fines representing other aggregates, particularly carbonates. Conclusions: Variability in the percentage of hydrated lime added to the mixture has a significant effect on the ignition furnace correction factor. The amount of sulfur present in the asphalt significantly affects the ignition furnace correction factor, but to a lesser degree than the lime content. Variabilitty resulting from both of these factors can be overcome if the furnace is properly calibrated and the amount of lime introduced in to the mix is controlled.

Brian D. Prowell, Senior Research Scientist, Virginia Transportation Research Council, 530 Edgemont Road, Charlottesville, VA 22903, Tel: 804-293-1919, Fax: 804-293-1990, ProwellBD@VDOT.state.va.us; and Jack Youtcheff, Ph.D., Senior Chemist, SaLUT – Federal Highway Administration, Turner-Fairbank Highway Research Center , 6300 Georgetown Pike, HRDI , McLean, VA 22101, Tel: 202-493-3090, Fax: 202-493-3160, Jack.Youtcheff@fhwa.dot.gov.

00-1094 "Detecting Segregation in Bituminous Pavements and Relating Its Effects to Condition"

Abstract: Field and laboratory studies were undertaken to determine the feasibility of detecting and quantifying segregation in hot mix asphalt pavements. Nineteen segregated and non-segregated pavements were selected. At each selected pavement, segregated areas were classified by visual observation as light, medium and heavy. One-minute nuclear density measurements were made, cores were taken and incinerated and gradation tests were performed. Statistical comparisons were made using t-tests to characterize the differences between nuclear-measured density and percent passing various sieves. The criterion that was used to detect segregation is based on statistical differences in nuclear density measurements with p-value less than 10^-3. The effects of segregation on pavement performance during the two-year period were also studied. Conclusions: Statistical differences in nuclear-measured density values can be used as an expedient indicator of segregation. Eighty and seventy percent of the nuclear density measurements supported the visual observations of heavy and medium segregation, respectively, when the significance of the differences (the p-value) between compared areas was less than 10^-3. Furthermore, gradation analyses confirmed that medium or heavy segregated areas have a coarser mix than that for non-segregated areas. The probability that significant differences in nuclear density measurements correspond to significant differences in aggregate gradation was 88 percent for the medium and heavy segregated areas. Comparisons made between lightly segregated and non-segregated areas did not show significant statistical differences. Raveling and cracking were the most commonly observed segregation-related distresses. Based on the distress data, heavy segregation causes a minimum of 50 percent decrease in pavement service life.

Chieh-Min Chang, Email: changc13@msu.edu, Thomas F. Wolff, Tel: 517-355-5128 Fax: 517-432-1356, Email: wolff@egr.msu.edu, Gilbert Y. Baladi, Tel: 517-355-5147 Fax: 517-432-1827, Email: baladi@egr.msu.edu, Department of Civil and Environmental Engineering, Michigan State University, 3546 Engineering Building, East Lansing, MI 48824-1226.

00-1237 "Identification and Assessment of Construction-Related Asphalt Concrete Pavement Temperature Differentials"

Abstract: This study examined four 1998 WSDOT paving projects to determine the existence and extent of mat temperature differentials and associated material characteristics. An infrared camera was used to identify cooler portions of the mat, which were then sampled along with normal-temperature pavement sections. Gradation and asphalt content analysis showed no significant aggregate segregation within the cooler areas. However, these cooler portions of the mat consistently showed higher air voids than the surrounding pavement. The higher air void areas in the mat may result in premature failure when compared to the mat as a whole. Conclusions: While none of the four projects showed significant aggregate segregation, all four showed temperature differentials. Temperature differentials are easily identified during construction with such instruments as an infrared camera. These cooler mat areas, if they occur, generally do so at the beginning of each AC truckload as it passes through the paver. On average, about four percent higher air voids were associated with the cooler mat areas. Good paving practices, including remixing, can reduce the effects of significant mix temperature differentials. This study proved to the Washington State DOT that large temperature differentials are often detrimental to the laydown and compaction process. Specific factors such as ambient temperatures, haul times, truck factors, remixing, etc were studied during the 1999-paving season. The 1999 results will be reported in a future paper and report.

Joe Mahoney, Box 352700, University of Washington, Seattle, WA 98195-2700, Tel: 206-685-1760, Fax: 206-543-1543, Email: jmahoney@u.washington.edu; Stephen Muench, Perteet Engineering; Steven Read, Pavement Consultants Inc.; Linda Pierce, and Jeff Uhlmeyer, Washington State DOT; Herb Jakob, Astec Industries; Robyn Moore, Sverdrup Civil Inc.

00-1454 "Compaction Temperatures for Asphalt Mixtures Produced with Modified Binders"

Abstract: One of the main concerns with using modified asphalts is the need to heat the majority of these materials to very high temperature in order to achieve the viscosity of 0.280+/- 0.020 Pa-s specified for compaction. This heat can lead to their thermal degradation and can raise other environmental and safety issues. This study was focused on measuring the effect of several modified asphalts on the densification characteristics of mixtures conducted using the Superpave Gyratory Compactor (SGC) at various temperatures. Detailed evaluations of the viscosity profiles of the modified asphalts at a wide range of temperatures and shear rates were measured. Several models were used to represent the non-Newtonian behavior. The viscosity characteristics were related to the change in air voids of the asphalt mixtures to quantify the effect of temperature, viscosity, and non-Newtonian behavior on compaction. It is found that viscosity at lower shear rates can be used to explain the differences observed in compaction of the mixtures with the modified asphalt. A model was selected and used to estimate the Zero Shear Viscosity (ZSV) at a range of temperatures. A proposal is introduced to use the ZSV to estimate the compaction temperature for modified binders. Conclusions: Modified binders show significant shear rate dependency. The Cross-Williamson model is found to be a good choice to represent the dependency of asphalt binders’ viscosity on shear rate. The SGC compaction data indicates that there is significant effect of viscosity on the level of air voids that could be achieved. The relationship between percent air voids and the logarithm of viscosity of the binders is found to be approximately linear. Using the viscosity at lower shear rates, the effect of binder type can be normalized such that for the same Zero Shear Viscosity (ZSV), the same air voids are expected regardless of the nature of the binder used. To keep the compaction temperature within reasonable range, the zero shear viscosity of 6.0 Pa-s is proposed as a target for compaction. Results indicate that the SGC compaction procedure can result in required air voids content at the same number of design gyrations specified. It is therefore believed that this target viscosity will not require changes in compaction effort and will result in a negligible increase in asphalt content.

Hussain Bahia and Arif Khatri, University of Wisconsin – Madison, 1415 Engineering Drive, 2210 Engineering Hall, Madison, WI 53706, Tel: 608-265-4481, Fax: 608-262-5199, Email: bahia@engr.wisc.edu.

00-1457 "An Evaluation of Notched Wedge Longitudinal Joint Construction"

Abstract: The proper construction of longitudinal joints is critical to the overall performance of a hot mix asphalt (HMA) pavement. Many times the in-place density at and across the longitudinal joint is substantially lower than the density of the remainder of the HMA surface. This low in-place density increases the potential for development of cracking and raveling to develop along the joint. Research has shown that the use of the notched wedge joint has the potential to increase the density at the longitudinal joint, which should result in a longer-lasting pavement. The notched wedge joint was compared to conventional longitudinal joint construction techniques on projects in five states (Colorado, Indiana, Alabama, Wisconsin, and Maryland). The evaluation consisted of comparing the in-place density obtained through pavement cores at five locations across the longitudinal joint of the pavement (at the centerline, 150 mm (6 in.), and 450 mm (18 in.) on either side of the centerline. The results of the study indicated that the notched wedge joint can be used successfully to increase the in-place density at the longitudinal joint. Some decrease in the in-place density was observed at the 150 mm (6 in.) second lane (hot side) location when using the notched wedge joint, possibly as a result of insufficient compaction in the wedge portion of the joint. Additionally, the use of the notched wedge joint greatly reduces the amount of paved to unpaved lane drop-off which should provide for a safer joint for the traveling public.

Shane Buchanan, National Center for Asphalt Technology, 211 Ramsay Hall, Auburn University, AL 36849, Tel: 334-844-6334, Fax: 334-844-6248, Email: buchams@eng.auburn.edu.

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4. Construction: Structures

00-1155 "Cold Weather Cast-in-Place Segmental Construction of Long Span Bridges"

Abstract: An innovative heating and monitoring method was developed and employed for wintertime casting of the Wabasha Street Bridge in Saint Paul, Minnesota. The bridge's twin 1,260 ft (384 m) concrete box girder spans are composed of two 400-ft-long (122 m) center spans, and two 230 ft (70 m) approach spans. Each deck contains two travel lanes with shoulders and a sidewalk. The superstructure haunch is 20 ft (6.10 m) deep over the piers and 8 ft (2.44 m) deep at mid-span and the abutments. The bridge was constructed in balanced cantilever fashion with form travelers. To insulate and protect the curing concrete, reinforced plastic enclosures surrounding the form travelers housed three 300,000 BTU (316,761 k-joule) propane heaters. A layer of plastic and a double layer of insulating blankets covered the top slab. Thermocouples in the segments provided temperature readings, which the contractor used to monitor the effectiveness of the cold weather procedures. The forms, reinforcing steel and previous concrete were heated above 50?F (10?C) using plastic enclosures, propane heaters and insulating blankets. The concrete arrived from the batch plant at approximately 70?F (21?C) and was still above 55?F (13?C) when pumped into the segments. Multiple thermocouples indicated that the top slab cured above 100?F (38?C) for several days, while the bottom slab and webs were about 20?F (-7?C) warmer. The contractor ran the propane heaters for five days after each pour, or until the segments reached a 28-day strength of 6,000 psi (41,340 kPa). The segments reached the required 3,500 psi (24,115 kPa) strength for post-tensioning on the day following each pour, including pours made on days as cold as -19?F (-28?C). Conclusions: Key elements that led to success of casting in the cold weather were; pre-pour meetings well before cold weather casting operations, concrete batch plant near the construction site, high-early strength concrete mix, redundancy in the protection system, and providing heat early to the segments (heat applied early during curing is more efficient). The pre-pour meetings were perhaps the most important aspect for the success of cold weather casting for the Wabasha Street Bridge. Teamwork also played an extremely important role because everyone (suppliers, crews, inspection staff, etc.) had to work efficiently to place concrete quickly to avoid over-exposure. Only three working days were lost due to the cold, and the bridge was completed on time. The method of heating and protection used at the Wabasha Street Bridge proved that the cast-in-place construction method is a viable option in cold weather climates on major long span bridges.

Christopher J. Burgess, Figg Bridge Engineers, Inc., 1873 S. Bellaire St. #1025, Denver, CO 80222, Tel: 303-757-7400, Fax: 303-757-0698, Email: chris.burgess@mindspring.com.

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5. Facilities, Equipment Design, and Performance

00-0157 "Effects of Right-Turn Lanes on Driveway Sight Distance"

Abstract: Vehicles entering a driveway from an exclusive right-turn lane may restrict the sight distance available to vehicles waiting to enter the arterial street from the driveway. The sight distance available to the vehicles waiting at a driveway is a function of the geometric design of the driveway and the right-turn lane. The relationship between available sight distance and the relevant geometric design variables is examined in this paper. The analysis identifies geometries that provide adequate sight distances for various design speeds. Conclusions: The results of the analysis presented in this paper indicate that right-turn lanes much wider than normal are needed to provide adequate sight distance for driveway vehicles to enter arterial streets with design speeds from 60 to 100 km/hr. The required right-turn lane widths would typically include a channelization island between the right-turn lane and the adjacent through lane. The stopping position of the driveway vehicle has a very pronounced effect on the overall width of right-lane required. Stopping positions closer to the roadway reduce the width required. However, pedestrian considerations may limit the extent to which the stopping position can be moved closer to the roadway. The need to provide wider right-turn lanes to improve driveway vehicle sight distance is eliminated if the traffic on the arterial street is controlled by a stop sign or traffic signal. Also, the temporary nature of the sight restrictions caused by traffic in the right-turn lane must be considered. The volume and arrival distributions of traffic on the arterial street and using the driveway determine the probability that this sight distance problem exists. Low traffic volumes and/or coordinated traffic flow on the arterial street may minimize the extent to which the problem occurs and the need to address it.

George R. Zeidan and Patrick T. McCoy, Department of Civil Engineering, W348 Nebraska Hall, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0531, Tel: 402-472-5019, Fax: 402-472-8934, Email: pmccoy@unlinfo.unl.edu.

00-0332 "Turn Lane Storage Length Design: Theory for the Practitioner"

Abstract: Transportation engineers use statistical distributions to determine the needed storage lengths of auxiliary left- and right-turn lanes. This paper reviews the theory behind the common design approach, takes actual field data to show shortcomings with the common design approach, and discusses other storage length design perspectives and tradeoffs. For eight or more turning vehicles per cycle and cycle lengths of 120 s or more, the commonly-used Poisson equation did not predict observed turn demand as well as the binomial model did. For these situations, the needed storage length can be estimated by subtracting one vehicle from the number predicted by the Poisson process. The common "double the mean" rule-of-thumb often overpredicted the number of turning vehicles. With this information, design engineers can better understand the relative strengths of various approaches and be more comfortable with a degree of flexibility in turn lane storage length design.

J. L. Gattis, Ph.D., P.E., Mack-Blackwell Transportation Center, University of Arkansas, 4190 Bell Engineering Center, Fayetteville, AR 72701. Tel: 501-575-7586, Fax: 501-575-7168, Email: jgattis@engr.uark.edu.

00-0347 "Visual Perception of Horizontal Curves in Three-Dimensional Combined Alignments"

Abstract: Traffic safety is an important element in roadway design, that is considerably affected by human factors. Among these factors is the drivers’ perception of the road ahead, which affects their decisions and actions. Thus, an erroneous perception of the road can lead to erroneous actions, and hence can compromise the traffic safety. Experimental evidences have shown that combined horizontal and vertical alignments can cause a wrong perception of the horizontal curvature and can affect the drivers’ choice of operating speed on horizontal curves. This paper examines the hypothesis that the driver’s perception of the horizontal curvature depends on the overlapping vertical alignment. Computer animation was selected as a three-dimensional presentation method of the road perspective, and was found to produce a realistic view of the road. A sample of drivers was interviewed, where they were asked to determine the horizontal curvature (overlapping with a level vertical grade) that matched a specific horizontal curvature (overlapping with a vertical curve). The results showed that the horizontal curvature looked consistently sharper when overlapping with a crest vertical curve and consistently flatter when overlapping with a sag vertical curve. The data, though preliminary and limited in size, showed that the perception of the horizontal curvature did not depend on the turning direction or the algebraic difference of the vertical curve grades. Further investigation is required to examine the effect of these factors and other alignment parameters on the perceived radius of horizontal curves more accurately and conclusively. It was established in the paper that crest vertical curves cause overlapping horizontal curves to look sharper while sag vertical curves cause overlapping horizontal curves to look flatter than what they actually are. Within the limited size of data points collected, the perceived radius of the horizontal curve did not depend on the turning direction or the algebraic difference of grades of the vertical curve. However, this latter finding may have been affected by the large standard deviation caused by using a large step in the radius of reference curves. Therefore, more research is required by extending the work described in this paper to include larger sample size, more curve parameters, and finer step in the radius of reference curves.

Yasser Hassan and Said Easa, Lakehead University, Thunder Bay, Ontario, Canada, P7B 5E1, Tel: 807-343-8571, Fax: 807-343-8928, Email: seasa@gale.lakeheadu.ca.

00-0980 "Acceleration Characteristics of Starting Vehicles"

Abstract: Acceleration characteristics of starting vehicles are needed for many transportation design purposes involving driveways, turning bays, intersecting streets, traffic signals, railroad crossings, etc. Constant acceleration is sometimes assumed or AASHTO Green Book values based on piecewise-constant accelerations are sometimes adopted. Yet, continuing research has shown linearly-decreasing acceleration rates to better represent vehicle acceleration capabilities as well as actual motorist behavior. The evolution of AASHTO acceleration values for design is traced, and the literature is reviewed for pertinent field observations. Linearly-decreasing acceleration model parameters are calibrated for various sets of observational and design data. Despite published results from thousands of field measurements, design values seem to be based mostly on vehicle performance capabilities with conjecture about how much of these capabilities are normally used by drivers. Design accelerations are shown to deviate substantially from observed accelerations. Observed accelerations began about 15% faster for passenger cars and 45% faster for SU trucks than design accelerations. As speed increased, observed accelerations dropped 3 to 4 times faster than design accelerations for these vehicles. Observed accelerations for WB-15 trucks began 40% to 75% slower than design accelerations. For railroad crossings, the average acceleration rate from stop recommended to accommodate most trucks is about

1/3 of what is used in the Green Book. Voids in the available information base are identified. Linearly-decreasing design acceleration rates for motorists operating different classes of vehicles in different design situations are recommended, and revisions for Green Book parameters and charts are suggested. The recommended acceleration model greatly simplifies acceleration parameters, but implies using different acceleration relationships for different design speeds instead of one for all.

Gary Long, Ph.D., P.E., University of Florida, P.O. Box 116580, Gainesville, FL 32611-6580, Tel.: 352-392-7575, Fax: 352-392-3224, Email: long@ce.ufl.edu.

00-1627 "Predicting Operating Speeds on Tangent Sections of Two-Lane Rural Highways"

Abstract: The prediction and estimation of speeds on two-lane rural highways are of enormous significance to planners and designers. The estimation of speeds on curves may be easier than the prediction of speeds on tangent sections because of the strong correlation of speeds on a few defined and limiting variables, such as curvature, superelevation, and the side-friction coefficients between road surface and tires. On tangent sections, however, the speed of vehicles is dependent on a wide-array of roadway characteristics, such as the length of the tangent section, the radius of the curve prior to and after the section, cross-section elements, vertical

alignment, general terrain, and available sight distance. This research analyzed the variability of the operating speeds on 162 tangent sections of two-lane rural highways and developed models for its prediction based on the geometric characteristics available. Conclusion: After considerable examination of the sites, the data were assembled into four groups of similar characteristics: Group 1 (small radii and short tangent length); Group 2 (short radii and intermediate tangent length); Group 3 (intermediate radii and intermediate tangent length); and

Group 4 (any radius and long tangent length). Separate prediction models for the 85th percentile speed were developed for each of the four groups separately. The models for Groups 1 and 2 sections provided a good fit to the data and could be adapted for prediction purposes during the planning process for new two-lane highways. The models for Groups 3 and 4 sections were preliminary, and clearly need additional data.

Abishai Polus, Technion-Israel Institute of Technology, Haifa, Israel 3200, Email: Polus@techunix.technion.ac.il; Kay Fitzpatrick and Daniel B. Fambro, Texas Transportation Institute, College Station, TX 77843-3135, Tel: 409-845-7321, Fax: 409-845-6481, Email: K-fitzpatrick@tamu.edu.

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6. Bituminous Materials

00-1364 "Field Validation of the New Superpave Low-Temperature Binder Specification Procedure Using Performance Data from the Pennsylvania Test Sections"

Abstract: Recently a new specification procedure was proposed to determine the low-temperature performance grade (PG grade) of asphalt binders. This new procedure uses Bending Beam Rheometer (BBR) and Direct Tension Test (DTT) data at two temperatures to determine the low-temperature grade of an asphalt binder. A study was conducted to validate this procedure by using asphalt binder retained samples from the widely published test road in Pennsylvania. This road was constructed in 1976 in Elk county, PA and performance including low-temperature transverse cracking index was monitored over six years. In this study the retained binder samples from the six test sections T1 to T6 were tested with the BBR and the new Superpave DTT. The data from these two tests were analyzed to obtain critical cracking temperatures and low-temperature PG grades. Results indicate that the new procedure correctly predicts the temperature at which cracking was observed in the field. Conclusions: The current Provisional AASHTO binder specification provides adequate low temperature performance prediction for some binders, there are, however, cases where they both over-predict and under-predict performance. Field performance data from the Pennsylvania Test Road and on two polymer-modified asphalts validates the concepts put forth in a recently developed comprehensive procedure for determining critical cracking temperature (reference 10). The new procedure incorporates a mechanistic model that enables calculation of better predictive parameters from the BBR and DTT data to determine the relative performance of asphalt binders at low service temperatures. This procedure uses rheological data from the BBR to predict thermal stress build up and fracture data from the DTT to predict failure stress.

Raj Dongré, Ph.D, Federal Highway Administration/DLSI, 6300 Georgetown Pike, McLean, VA 22101, Tel: 202-493-3104, Fax: 703-527-4012, Email: rajdongre@yahoo.com; Mark G. Bouldin, Ph.D, Koch Materials Company,

4027 E. 37^th Street North, Wichita, KS 67220, Tel: 316-828-4472, Fax: 316-828-6025, Email: bouldinm@yahoo.com; and Dean A. Maurer, Pennsylvania Department of Transportation, 1118 State Street, Harrisburg, PA 17120, Tel: 717-787-5229, Fax: 717-787-5955.

00-1389 "Real Time Process Control of Binders During Blending and HMA Production"

Abstract: This research was based on several hypotheses: 1) internal changes in morphology of a modified asphalt will be seen as changes in viscosity, 2) over a narrow range of high temperatures, both neat and modified asphalts have a linear (on a log scale) viscosity-temperature relationship, 3) this relationship when established at the time the binder is certified, can be used to predict a viscosity from the temperature of the in-line product, and 4) if the measured in-line viscosity differs substantially from the temperature-predicted viscosity, then there is a reasonable expectation that the product being produced will have a significant difference in at least one of the Superpave binder properties. The research was conducted in two phases: Phase 1 installed a Brookfield concentric cylinder in-line viscometer in a Minnesota blending terminal in the fall of 1998. The design of the in-line viscometer is consistent in design concepts used for determining high temperature viscosities in the laboratory. Data collected from this research showed that monitoring viscosity differences during the loading of binder trucks identified significant increases in binder stiffness approximately one week before the refinery identified a continual but gradual increase in the cold temperature stiffness properties of the base asphalt. The phase 1 research also resulted in a recommendation to modifying the viscometer design so that the temperature sensor was placed directly in the measurement well. Phase 2 installed two modified viscometers, one in a Michigan blending terminal and the second in a Michigan high capacity hot mix asphalt (HMA) plant which purchased binders from the terminal. Preliminary results indicate that binders are typically produced within about 10 to 12 percent of the anticipated laboratory viscosity. This range of viscosity does not appear to change by the time unmodified material is used at the plant. The viscosity of modified asphalt increases as the tank is used. That is, the bottom one-third of the tank has a significantly higher viscosity than the top one-third. Testing is being completed to ascertain any corresponding changes in the Superpave binder properties.

Mary Stroup-Gardiner, Auburn University, 236 Harbert Engineering Center, Auburn, AL 36849; Tel: 334-844-6280; Email: marysg@eng.auburn.edu.

00-1096 "Evaluation of OGFC Mixtures Containing Cellulose Fibers"

Abstract: Open-graded friction courses (OGFCs) are special purpose mixes used to improve friction, minimize hydroplaning, reduce splash and spray, improve night visibility, and lower pavement noise levels. OGFCs typically utilize a gap-grading for aggregates and a low percentage of filler. Asphalt contents for OGFCs are generally slightly higher than for dense-graded mixes. The combination of uniform-grading, low filler, and normal OGFC asphalt contents can lead to the asphalt binder draining from a mix during transportation and laydown procedures (typically called draindown). States that use OGFC typically utilize fibers to help prevent draindown. Generally, these states have specified mineral fibers over organic fibers because of the fear that organic fibers (cellulose) would absorb water and lead to moisture problems in the field. This study was conducted to evaluate the use of cellulose fibers in OGFC mixes. The study entailed both a field and laboratory phase. Field work entailed conducting a visual distress survey of six experimental OGFC pavements placed in Georgia during 1992. These pavements contained six different combinations of binder polymer and additives and included sections with cellulose and mineral fibers. Laboratory work entailed preparing OGFC mixes with both cellulose and mineral fibers and performing numerous moisture sensitivity tests. Results indicated that cellulose fibers performed as well as mineral fibers in OGFC mixes.

L. Allen Cooley, Jr., Research Engineer, National Center for Asphalt Technology, 211 Ramsay Hall, Auburn, AL 36849, Tel: 334-44-6336, Fax: 334-844-4485, Email: coolela@eng.auburn.edu; E. Ray Brown, Director, National Center for Asphalt Technology, 211 Ramsay Hall, Auburn, AL 36849, Tel: 334-844-6228, Fax: 334-844-6248, Email: rbrown@eng.auburn.edu; and Donald E. Watson, Georgia Department of Transportation, Office of Materials and Research, 15 Kennedy Drive, Forest Park, GA 30297, Tel: 404-363-7521, Fax: 404-363-7684.

00-1228 "Cold In Place Recycling on Kansas US-283"

Abstract: An experimental partial depth cold in-place recycling (CIR) project was performed on Kansas US-283 in 1997. Two approximately equal sections in length, one with Class C fly ash and the other with an emulsion with lime slurry, were recycled. Both sections had an HMA overlay placed after curing. Field observations in 1998 showed minor transverse cracking in the fly ash section, with no cracking evident in the emulsion plus lime section. Transverse cracking increased in the fly ash section in 1999, and was noticed for the first time in the emulsion plus lime section during this same evaluation. Longitudinal cracking in the wheel paths of the fly ash section was also first observed in 1999. Rutting was not observed in either section during the evaluations. The results of Superpave Indirect Tensile (IDT) laboratory testing confirmed that the fly ash section should crack before the emulsion with lime section; laboratory testing with the Superpave Shear Tester and the Asphalt Pavement Analyzer also indicated that the mixtures were not susceptible to rutting. Conclusions: A distress survey was performed in November 1999. Transverse cracks were measured in three fly ash sections and three emulsion with lime slurry sections, each 500 feet in length. A total of 711 feet of cracking in the three fly ash sections was measured, and 369 feet in the emulsion lime slurry sections. The fly ash section is also showing longitudinal cracking throughout much of the length of the section and no to little longitudinal cracking in the emulsion plus lime slurry sections. The longitudinal cracks are believed to be load associated. The tendency of the fly ash section for greater fatigue damage is indicated by the greater stiffness as measured in shear modulus testing.

Todd Thomas, P.E., 316-828-6737, thomast@kochind.com and Arlis Kadrmas, 316-828-8994, kadrmasa@kochind.com, Fax: 316-828-7385, Koch Materials Company, P.O. Box 1875, Wichita, KS 67201; and John Huffman, P.E., 785-827-4439, Fax: 785-825-2457, Brown & Brown, Inc., P.O. Box 2000, Salina, KS 67402.

00-1397 "Evaluation of Uncompacted Void Content of Fine Aggregate as a Quality Indicator of Materials Used in Superpave Mixtures"

Abstract: The uncompacted void content of fine aggregate, or fine aggregate angularity (FAA), was introduced in the Superpave mixture design system to screen smooth and/or rounded fine aggregates that may result in mixtures with low rutting resistance. The presumption is that fine aggregates with lower FAA values have lower shear strength (internal friction) and lower resistance to rutting. Continued implementation and evaluation of the Superpave system has led to numerous questions regarding the validity of this assumption and of the use of FAA in general. Nine fine aggregates were evaluated in this study to evaluate the FAA test and to determine whether FAA was a reliable indicator of fine aggregate shear strength. FAA tests were performed using three gradations and the three standard test methods (A, B, and C). Microscopic analysis was conducted to obtain independent visual measures of angularity and texture. Direct shear tests were performed at four confining stresses to determine shear strength parameters. Results indicated that FAA was related to visual measures of texture and angularity. However, although FAA contributed to shear strength, it appeared that other factors such as toughness, gradation, and packing characteristics of the fine aggregate overshadow its effect. For the fine aggregates tested, FAA rejected aggregates with high shear strength, while accepting aggregates with low shear strength. It was concluded that FAA alone may not be adequate to assess shear resistance of fine aggregate. Direct shear strength may be a better parameter, but additional work is required to evaluate its validity and feasibility.

Jose L. Fernandes, Reynaldo Roque, Mang Tia, and Lorenzo Casanova, Department of Civil and Coastal Engineering, PO Box 116580, University of Florida, Gainesville, FL 32611-6580, Tel: 352-392-7368, Fax: 352-392-3394, Email: rroqu@ce.ufl.edu.

00-1055 "Flagstaff I-40 Asphalt Rubber Overlay Project Nine Years of Success"

Abstract: In 1990, the Arizona Department of Transportation designed and constructed a large scale asphalt rubber test project in Flagstaff, Arizona on the very heavily trafficked Interstate 40. The purpose of the test project was to determine whether a relatively thin overlay with asphalt rubber could reduce reflective cracking. Asphalt rubber is a mixture of 80% hot paving grade asphalt and 20% ground tire rubber. This mixture is commonly referred to as the asphalt rubber wet process or McDonald process. The overlay project was built on top of a very badly cracked pavement, which was in need of reconstruction. The asphalt rubber overlay has performed beyond the original expectation. After nine years of service the overlay is still virtually crack free, with good ride, virtually no rutting or maintenance and good skid resistance. The benefits of using asphalt rubber on this project represents about $18 million dollars in construction savings and four years less construction time. Strategic Highway Research Program SPS-6 test sections built in conjunction with the project further illustrates the very good performance of the asphalt rubber. Results of this project have led to widespread use of asphalt rubber hot mixes throughout Arizona. Based upon this work over 3,333km(2,000 miles) of successfully performing asphalt rubber pavements have been built since 1990. Conclusions: Based upon the outstanding performance of this project as well as many others, the Arizona Department of Transportation uses asphalt rubber gap graded and open graded mixes throughout the state. Even though asphalt rubber mixes cost about twice as much per ton, they are generally placed half as thick and crack at a rate less than one fourth than that of conventional hot mix asphalt.

George Way, Arizona Department of Transportation, Materials Group, 1221 N. 21^st Ave., Phoenix, AZ 85009, Tel: 602-712-8085, Fax: 602-712-8138, Email: gway@dot.state.az.us.

00-1099 "Selection and Evaluation of a Field Permeability Device for Asphalt Pavements"

Abstract: This paper presents the results of a study conducted to select, standardize and evaluate a device to estimate the in-place permeability of hot mix asphalt (HMA) pavements. The study consisted of evaluating four different field permeameters in order to select and standardize a device that was correlated with laboratory permeability results, repeatable, and easy to use. Additional testing on five HMA pavements was conducted with the selected device in order to evaluate the relationship between in-place pavement density and field permeability. The study entailed visiting three on-going construction projects and conducting field permeability tests on newly compacted HMA pavements with each device. Also at each project, cores were obtained from which the laboratory permeability was determined. The data from each project was analyzed to determine which field permeameter correlated best with laboratory permeability, was the most repeatable, and was easy to use. Results of this study indicated that two permeameters did not show significant differences with laboratory permeability results and had approximately the same amount of repeatability. For this reason, a field permeameter was selected based upon ease of use. This selected device was then taken to five additional HMA construction projects. At each project, field permeability testing was conducted and the in-place density of pavements obtained via cores. Relationships between in-place air voids and field permeability for all five projects were good as R² values ranged from 0.63 to 0.82.

L. Allen Cooley, Jr., Research Engineer, National Center for Asphalt Technology, 211 Ramsay Hall, Auburn University, AL 36849, Tel: 334-844-6336, Fax: 334-844-4485, Email: coolela@eng.auburn.edu; and E. Ray Brown, Director, National Center for Asphalt Technology, 211 Ramsay Hall, Auburn University, AL 36849, Tel: 334-844-6228, Fax: 334-844-6248, Email: rbrown@eng.auburn.edu.

00-1206 "Asphalt Permeability Testing in Virginia"

Abstract: Because of high air voids, long-lasting damp spots on pavement surfaces, and reported problems that other states have had with permeable coarse Superpave mixes, The Virginia Department of Transportation (VDOT) decided to investigate the permeability of its mixes. The primary purpose of this investigation was to determine the general magnitude of permeability for mixes being used by VDOT, with an emphasis on testing Superpave mixes. Falling head permeability tests were performed on pavement cores to determine the general permeability of mixes. The permeability of some of the pavement cores were compared to permeability of specimens made in the lab, using mixtures sampled during construction to determine whether permeability tests on lab specimens could be used to predict pavement permeability. Conclusions: A large percentage of the field cores contained excessive voids and excessive permeability, which emphasizes the importance of achieving adequate pavement density. Each mix had a unique voids-permeability relationship. Mixes that were composed of large aggregates required fewer voids to achieve an acceptable level of permeability. In four out of five cases, lab tests were successful in indicating field permeability.

G. W. Maupin, Jr., Virginia Transportation Research Council, 530 Edgemont Road, Charlottesville, VA 22903, Tel: 804-293-1948, Fax: 804-293-1990, Email: maupingw@vdot.state.va.us.

00-1241 "Effects of Different Water Saturation Levels on the Resistance of Compacted HMA Samples to Moisture Induced Damage"

Abstract: The Florida Department of Transportation (FDOT) initiated the monitoring of its first Superpave section on I-75 in Columbia County for stripping potential. For such a purpose, the standard AASHTO T 283 test procedure was used. AASHTO T 283 specifies that all conditioned test samples be saturated to between 55 and 80 percent based on 7 ± 1 percent air voids. However, the potential interaction between air void content and the level of saturation has not been fully investigated. It is also not clear whether test results from samples saturated to 55 percent are comparable to those of the same mixture saturated to 80 percent for a similar air void content. Therefore, although FDOT adopted AASHTO T 283, it also initiated a parallel study on the effects of different degrees of saturation on moisture damage. The present paper summarizes the findings of both the on-going monitoring of the I-75 project for potential stripping and the investigation of the effects of different levels of saturation on moisture susceptibility test results as determined using AASHTO T 283. Conclusions: The findings indicated that after more three years of heavy traffic this pavement section has yet to experience any rutting or moisture-related surface distress, although some roadway cores exhibited visual evidence of stripping. The stripping seemed localized at the interface between the two Superpave mix layers, mainly in the coarse aggregate fraction. The TSR values on these cores ranged from 62 to 65 percent, while wet tensile strengths of as low as 360 kPa (52 psi) were recorded. Testing on laboratory reproduced samples indicated that the magnitude of the TSR values decrease with the increase of the level of moisture saturation. Further statistical analyses indicated a strong correlation between these TSRs and the level of saturation, regardless of the two mix types, when the freeze/thaw cycle was considered. Based upon the findings of the present study, recognizing the limited data and the complexity of the behavior of partially saturated asphalt mixtures under load, it is recommended that the test samples be saturated to more than 90 percent when using AASHTO T 283. It is also suggested that the conditioning phase include the optional freeze/thaw cycle. In addition, an appropriate passing TSR limit should be set to no less than 80 percent and air void content of test samples be reduced to 7 ± 0.5 percent. It is also suggested that a limiting strength criteria of not less than 410 kPa (60 psi) be set on the wet tensile strength.

Bouzid Choubane, Gale C. Page, and James A. Musselman, Florida Dept. of Transportation State Materials Office, 2006 N.E. Waldo Road, Gainesville, FL 32609, Tel: 352-337-3132, Fax: 352-334-1648, Email: bouzid.choubane@dot.state.fl.us.

00-1066 "Asphalt Mix Evaluations – A Case Study, San Francisco International Airport"

Abstract: This paper describes a forensic study of asphalt mix performance at the San Francisco International Airport (SFIA) using the SHRP-developed simple shear test. The study examined taxiways subjected to stationary and slow movements of heavy aircraft wheel loads and covered a period of about two and one-half years. The results of the study indicate the need to modify (or change) the current FAA criteria for mix design for asphalt mixes for heavy duty airfield pavements, particularly for taxiways used for takeoff operations and subjected to stop-and-go operations of heavy aircraft like the Boeing 747-400. Information presented suggests that the simple shear test conducted in repeated loading while maintaining the height of the specimen constant (RSST-CH) can be used as a replacement for the current FAA mix evaluation procedure using the Marshall test. Mix design criteria are presented and are based on satisfactory performance of a High Stability mix (consisting of all-crushed aggregate and an AR-16000 asphalt) introduced at SFIA for taxiways. Conclusions: The shear test equipment developed during the SHRP program provides a methodology suitable for mix design for taxiways subjected to heavy aircraft loading such as the Boeing 747-400. The procedure using this equipment defines the rutting propensity of a mix by means of a repetitive simple shear test at constant height (RSST-CH). Test results from shear tests on cores differentiate between those mixes that have shoved and rutted under Boeing 747-400 operations and the High Stability mix used at SFIA, which has performed satisfactorily. This latter observation is supported by laser profilometer measurements as well as by visual observation. Based on the experience obtained at SFIA, the repetitions, N, corresponding to 5 percent permanent shear strain should be a minimum of 25,000 when the test is performed at 50 °C (122 °F); a shear stress of 10 psi; a time of loading of 0.1 sec.; a frequency of about 86 stress applications per minute; and with the mix compacted by rolling wheel compaction to an air-void content in the range 3 to 4 percent. This, according to the information presented, provides a probability of satisfactory performance of about 0.5. If a higher level is considered desirable, e.g., 0.8, then value of N at 5 percent shear strain should be 100,000 for the same conditions.

Monismith, Carl L., John T. Harvey, Irwin M. Guada, Fenella Long, University of California at Berkeley, Pavement Research Center, 1353 S. 46^th Street, Bldg 452, Richmond, CA 94804, Tel: 510-231-9587, Fax: 510-231-9589, Email: clm@newton.berkeley.edu; Bernard A, Vallerga, W.A. Nokes, Nichols-Vallerga and Associates, Oakland, CA; and Adlai Jew, San Francisco International Airport, San Francisco, CA.

00-1105 "A Rational Approach Of Specifying The Voids In Mineral Aggregate For Dense-Graded Hot Mix Asphalt"

Abstract: The minimum voids in the mineral aggregate (VMA) requirements in Superpave are based on the nominal maximum aggregate size in the mix. These requirements are based on the original recommendations by McLeod for relatively fine-graded mixes. However, in view of the wide range of gradations used today especially in Superpave, questions arise whether the nominal maximum size is capable of differentiating aggregate gradations for a wide band of gradation, ranging from very fine to very coarse, and whether there is any other factor which is more closely related to coarseness or fineness of the gradation, and which defines VMA more closely compared to nominal maximum aggregate size. Since the gradation of the dense-graded mixture affects the asphalt binder film thickness present in the designed mix, it would seem logical and helpful to provide a minimum VMA requirement based upon the percent passing the 2.36 mm sieve for each nominal maximum aggregate size mix used in the Superpave system. Conclusions: From theoretical calculations of minimum VMA based on required film thickness for mixes with different percent passing the 2.36 mm sieve, it was observed that substantial differences in VMA exist among different permissible gradations of mix with the same nominal maximum aggregate size. VMA values for the different mixes are recommended on the basis of percent passing the 2.36 mm sieve, and 4.0 percent air voids in compacted mix. The VMA values for the 9.5 mm and 12.5 mm mixes were determined on the basis of surface area factors of aggregates passing the 2.36 mm sieve, and the values were increased by1.2 percent, to consider the contribution of the aggregates retained on 2.36 mm sieve. However, the VMA values for the 19.0 mm, 25.0 mm, and 37.5 mm nominal maximum aggregate size mixes were determined on the basis of surface area factors for aggregates passing the 2.36 mm sieve only.

Rajib B. Mallick, Worcester Polytechnic Institute, CEE Department, 100 Institute Road, MA 01609, Tel: 508-831-5289, Fax: 508-831-5808, Email: rajib@wpi.edu; Michael Shane Buchanan, Prithvi S. Kandhal, Richard L. Bradbury and Wade McClay.

00-1247 "Comparison of 100-mm and 150-mm Diameter Specimens in the Superpave Gyratory Compactor"

Abstract: Due to increasing traffic levels and vehicle wheel loads, it has become necessary to improve the effectiveness and efficiency of the design of Hot Mix Asphalt (HMA). The Superior Performing Asphalt Pavement (Superpave) mix design and analysis system was introduced for this purpose. The Superpave Gyratory Compactor (SGC) is a vital part of this new mixture design and analysis system. Currently, the SGC uses 150-mm diameter cylindrical molds to produce specimens for design and evaluation under the Superpave system. The objective of this study was to explore the potential for using 100-mm (4-inch) diameter molds to produce test specimens in the laboratory. Loose HMA was collected from over 40 paving projects throughout the state of Tennessee. The mixes were tested in the laboratory, and the relative density (%G_mm) of the 150-mm (6-inch) diameter specimens was statistically compared with that of the 100-mm diameter specimens. The results of paired t-tests conducted on the data indicate that the difference in %G_mm is statistically significant. However, further analysis of the data demonstrated that the observed difference in %G_mm is smaller than the documented precision of the laboratory test methods used. Thus, it is concluded that the observed difference has no "engineering" significance. Based on these findings, it has been recommended to the Tennessee Department of Transportation (TDOT) that it is feasible to use 100-mm diameter specimens in lieu of the 150-mm diameter specimens for design and analysis of HMA in Tennessee. This recommendation is limited to mixes with a nominal maximum aggregate size of 25.4-mm (1-inch) or less.

N.M. Jackson, L.J. Czor, The University of Tennessee, Department of Civil and Environmental Engineering, Knoxville, Tennessee 37996-2010, Tel: 423-974-7708, Fax: 423-974-2669, Email: nmjackson@utk.edu.

00-1323 "Mechanistic Evaluation of Hydrated Lime in HMA Mixtures"

Abstract: Permanent deformation and moisture damage are common distresses found in pavements today. The use of hydrated lime is known to provide decreases in moisture susceptibility. In many cases, mineral fillers will also increase the mixture stiffness. The objective of this research is to evaluate the fundamental engineering properties of asphalt concrete mixtures containing hydrated lime. Conventional asphalt concrete mixtures and mixtures modified with hydrated lime were examined. The fundamental engineering properties considered include indirect tensile strength and strain, permanent deformation characteristics, resilient modulus, and fatigue resistance. The Hamburg wheel tracking test device was also used in the performance evaluation. A typical Louisiana low volume dense graded mixture was used. The test factorial included two aggregate types: limestone and gravel; and two asphalt cement types: a conventional AC-30 and a SB polymer modified. The results indicated that the addition of hydrated lime as mineral filler improved the permanent deformation characteristics and fatigue endurance of the asphaltic concrete mixtures. This improvement was particularly apparent at higher testing temperatures with mixes containing polymer modified asphalt and limestone aggregate.

Louay N. Mohammad, Chris Abadie, Rana Gokmen, and Anand J. Puppala
Louisiana Transportation Research Center, 4101 Gourrier Lane, Baton Rouge, LA 70808, Tel: 225-767-9126, Fax: 225-767-9108, Email: louaym@lsu.edu.

00-1252 "Investigation of the Suitability of the Asphalt Pavement Analyzer for Predicting Pavement Rutting"

Abstract: This paper summarizes the findings of an investigation performed to evaluate a wheel tracking device, known as the Asphalt Pavement Analyzer (APA), for assessing the rutting potential of asphalt mixes. The evaluation process consisted of correlating the APA=s predicted rutting with known field measurements. The correlation between beam and gyratory samples as well as the testing variability were also investigated. In addition, the APA test results were compared to those obtained using the Georgia Loaded Wheel Tester. Conclusions: The findings of this investigation indicated that the APA may be an effective tool to rank asphalt mixtures in terms of their respective rut performance. However, for each mixture type, the APA testing variability was significant between tests and also between the three testing locations within each test. Ranges of rut measurements of up to 4.7 and 6.3 mm were, respectively, recorded for beam and gyratory samples. Therefore, using the APA in a clear pass/fail criteria for performance prediction purposes of asphalt mixtures may not be appropriate at the present time. It should be noted that these findings are based on data collected on three mixes. It is, thus, suggested that the APA testing variability (testing and testing locations within the device) be further assessed for a wider range of mixtures. The intent of such an assessment should not only be to correlate the APA results to field data, but also to develop potential pass/fail limits and procedures.

Bouzid Choubane, Gale C. Page, and James A. Musselman, Florida Deptartment of Transportation State Materials Office, 2006 N.E. Waldo Road, Gainesville, FL 32609, Tel: 352-337-3132, Fax: 352-334-1648, Email: bouzid.choubane@dot.state.fl.us.

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7. Cement and Concrete

00-1047 "Performance Evaluation of Combinations of Durability Enhancing Admixtures (Mineral and Chemical) in Structural Concrete"

Abstract: A literature review was undertaken on the performance of mineral and chemical durability enhancing admixtures used in structural concrete. It is part of a study to determine how combinations of mineral and chemical admixtures may offer dual protection to structural concrete in corrosive environments. Almost sixty papers and reports were reviewed, and considerable information was found about the performance of individual mineral and chemical admixtures. However, only a handful of the papers reviewed reported on use of combinations of mineral and chemical admixtures, and clear recommendations on their combined use are not currently available. Based on this literature review and a DOT survey of admixture usage, long-term laboratory corrosion tests are planned that will include various admixture combinations. Conclusions: Following is a summary of optimum dosages of chemical and mineral durability enhancing admixtures for structural concrete, per the literature review. Concrete with w/c < 0.50 was also typically recommended. Some optimum dosages, particularly for combinations of admixtures, are not well-established or based on extensive testing.

• Calcium nitrite: 15-25 L/m³.
• Amines and esters: 5 L/m³.
• Silica fume: 10%-15% cement replacement.
• Fly ash: 25%-30% cement replacement.
• Slag: 40%-50% cement replacement.
• Calcium nitrite and silica fume: 10-20 L/m³ and 7.5%-10% cement replacement, respectively.
• Calcium nitrite and fly ash: 10-20 L/m³ and 20%-30% cement replacement, respectively.
• Amines and esters and fly ash: 5 L/m³ and 20% addition by weight of cement, respectively.
• Silica fume and fly ash: 7.5%-15% cement replacement and 15%-30% cement replacement,respectively.
• Silica fume and slag: 5%-7.5% cement replacement and 25%-45% cement replacement, respectively.
• Fly ash and slag: 20% cement replacement and 45% cement replacement, respectively.

James M. LaFave, Department of Civil & Environmental Engineering, University of Illinois, 205 N. Mathews Avenue, Urbana, IL 61801, Tel: 217-333-8064, Fax: 217-265-8039, Email: jlafave@uiuc.edu; and Donald W. Pfeifer, Wiss, Janney, Elstner Associates, Inc., 330 Pfingsten Road, Northbrook, IL 60062, Tel: 847-272-7400, Fax: 847-291-9599.

00-1216 "Mititgation of Alkali-Silica Reactivity in New Mexico"

Abstract: Alkali-silica reaction occurs when reactive silica in aggregates chemically reacts with alkaline components of Portland cement forming ASR gel. When the relative humidity of the gel exceeds about 80 percent, the gel absorbs water producing swelling which causes distress in the concrete. Aggregates throughout the central valley in New Mexico are of volcanic origin and minerals known for their reactivity with cement alkalis. In the summer of 1997 the NMSHTD, Research Bureau initiated an experiment to develop data for use in specifying methods to eliminate ASR damage in Portland cement concrete. The work was performed by the Materials Research Center, ATR Institute, University of New Mexico. The work involved using accelerated mortar bar tests to identify additives and combinations of additives that reduce expansion to acceptable levels based on the accelerated tests. The additives investigated were several fly ash materials used in New Mexico and lithium nitrate solution. Test results indicate that ASR may be controlled through the selection of a minimum amount of Class F fly ash in the range 25 to 27 percent by weight of total cementitious material. A combination of Class F fly ash and lithium nitrate reduced the amount of fly ash necessary. However, the accelerated test is not a fair representation of the effects of lithium nitrate because about half of the lithium nitrate is leached out of specimens during the test. A subsequent investigation was conducted to evaluate the effect of lithium nitrate on concrete strength. It was found for both air entrained and non-air entrained concrete, the strengths were not affected except for a slight increase.

R. Gordon McKeen, Lary R. Lenke, Kiran K. Pallachulla, ATR Institute, University of New Mexico; William L. Barringer, New Mexico State Highway and Transportation Department, 1001 University Boulevard SE, Suite 103, Albuquerque, New Mexico 87106-4342, Tel: 505-246-6410; Fax: 505-246-6001, Email: gmckeen@unm.edu.

00-0968 "92-MPa Air-entrained HPC Using Tennessee Materials"

Abstract: An air-entrained HPC mixture design for pre-stressed bridge beams was developed in an attempt to interest the Tennessee Department of Transportation. The mixture contained locally-available, 19-mm maximum size limestone as the coarse aggregate and a manufactured limestone fine aggregate. A dense, combined aggregate gradation was used to lower water demand and thus enhance durability. Type II Portland cement, microsilica and Class C fly ash were used as binder materials. The resulting w/c+p was 0.22. Twelve 0.028-m3 batches of the HPC were mixed for the study. The mixture design was produced an average air content of 4.1% and an average slump of 72-mm. Although containing 4.1% air, the mixture remained very dense, the average unit weight was 2422 kg/m3. Average compressive strengths of 72.6, 63.3, 84.8, and 92.9 Mpa were achieved at simulated release, 7, 28, and 56 days, respectively.

Measured static modulus of elasticity at 28-days agreed with ACI 363R-92 equations within two percent. Further, after 600 freezing and thawing cycles, the average durability factor of two prismatic specimens was 100 and visible damage was minimal. Conclusions: Air-entrained HPC with a durability factor of 100 and compressive strength in excess of 92 MPa (13,000 psi) at 56-days can be produced with Tennessee materials. The average 28-day, measured static modulus of elasticity was within two percent of the value predicted by ACI 363R-92. Optimizing the combined aggregate gradation allowed an 8.3 percent lower water-to-cementitious-materials ratio with no detrimental effects on plastic properties. Neither 62 MPa (9000 psi) sulfur mortar or 70-durometer neoprene capping performed well at compressive strengths in excess of 83 MPa (12,000 psi). The up-scaled AASHTO TP 33 device developed to measure coarse aggregate angularity worked well.

L.K.Crouch, Ph.D., P.E., Heather Sauter, E.I.T., Jacob A. Williams, E.I.T., Tennessee Technological University, TTU Box 5015, Cookeville, TN, 38505, Tel: 931-372-3196, Fax: 931-372-6352, Email: hjs3512@tntech.edu.

00-1167 "Effect of Pumping on Properties of Bridge Concrete"

Abstract: The short-term effects of pumping on concrete is well documented, while the long-term effects on concrete durability is not known. Pumping of concrete is widely used in large highway projects due to convenience and economy of placement. Both types of effects were studied herein through collection and testing of 73 concrete samples from the Florida Department of Transportation (FDOT) bridge construction sites before and after pumping. The tests performed were Air Content, Slump, Unit Weight, Compressive Strength, Rapid Chloride Permeability, and Water Permeability. The air content and slump of the concrete decreased by about 1% and 13 mm (0.5 in) on the average, respectively, due to pumping. The unit weight and compressive strength of concrete were found to increase by about 24 kg/m³ (1.5 pcf) and 1.83 MPa (266 psi), respectively, due to pumping. Pumping decreased the water and chloride ion permeability in the majority of tested samples. Results show that pumping does not have detrimental effects on concrete properties. In many cases, it results in stronger, denser, and more durable concrete. It is suggested that pumping be continued as a means of concrete placement in FDOT projects with confidence.

Nur Yazdani, Civil Engineering Department, Florida A&M University-Florida State University College of Engineering, 2525 Pottsdamer Road, Tallahassee, Florida 32310; Tel: 850-410-6125; Fax: 850-410-6142; Email: yazdani@eng.fsu.edu, Mike Bergin and Ghulam Mujtaba, Florida Dept. of Transportation, State Materials Office, 2006 N.E. Waldo Road, Gainesville, FL 32609, Tel: 352-337-3248, Fax: 352-334-1649, Email: mbergin@dot.state.fl.us.

00-1425 "Detecting the Extent of Corrosion Damage with Acoustic Emission"

Abstract: In this study reinforced concrete beams were tested in flexure and the acoustic emission (AE) response was recorded. Concrete beams (plain, notched-plain, reinforced, and corroded-reinforced) were prepared to isolate these damage mechanisms and the characteristic AE response associated with micro-crack development, localized crack propagation, corrosion, and debonding of the reinforcing steel was recorded. The AE response was analyzed to obtain key parameters such as the total number, rate, amplitude, and duration of the AE events. Analysis of the AE signal has shown that the extent of corrosion can be detected with acoustic emission measurements. Conclusions: Typically, distributed micro-cracking has a relatively low amplitude and short duration, whereas debonding cracks have a higher amplitude and longer duration. It was observed that when previously corroded beams were loaded, the primary AE signals were of high amplitude, and had longer duration, indicating predominance of bond degradation due to corrosion. Fewer AE events were recorded during loading for the corroded beams as compared to those, which were uncorroded. As the degree of corrosion increased the damage accrued during the corrosion process. Thus the incremental loading for the corroded beam resulted into lower incremental damage than that recorded for the uncorroded beams. The Felicity ratio (ratio between load level at which acoustic events occur and the previous load level) provides a criterion to evaluate the existing damage level in the reinforced concrete structure and correlates reasonably well with the specimen stiffness degradation. By applying a small incremental loading, and analyzing the reulting AE signals, it should be possible to detect the extent of corrosion for existing bridge decks. .

Surendra P. Shah, Center for Advanced Cement Based Materials, 2145 Sheridan Road, Suite A130, Evanston, IL 60208-4400, Tel: 847-491-3858, Fax: 847-467-1078, Email: s-shah@nwu.edu.

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8. Mineral Aggregates

00-0691 "Fine Aggregate Angularity: Automated Image Analysis Approach"

Abstract: Angularity is one of the important aggregate properties contributing to the permanent deformation resistance of asphalt mixtures. In the Superpave system, the fine aggregate angularity is defined in terms of the percent air voids present in loosely compacted aggregates. The underlying principle is that higher void contents indicate more fractured faces. Recent experience with the current Superpave criterion shows that there are cases where the test does not discern poor quality from high quality fine aggregate. Therefore, methods that are able to rapidly and accurately describe aggregate angularity are needed to improve the design process of asphalt mixtures. This study presents two computer-automated procedures, which make use of the advances in imaging technology, to quantify fine aggregate angularity. The proposed techniques were used to capture the angularity of twenty-three fine aggregate samples that represented a wide range of materials. The results were compared with visual analysis and indirect methods of measuring fine aggregate angularity, such as the uncompacted air voids, and the angle of internal friction of aggregate mass. Conclusions: The results indicated the advantage of the imaging techniques in rapidly and accurately capturing angularity independent from other aggregates characteristics. The indirect methods are shown to be limited in this regard as they rely on the bulk properties of aggregates, and their results are influenced by several aggregate characteristics such as angularity, gradation, texture, and elongation. The imaging parameters compared well with the visual analysis of angularity. A possible limitation of the imaging techniques is the number of particles that should be analyzed in order to represent an aggregate sample. Efforts are currently underway to develop an automated procedure to capture images of a large number of particles, and to investigate the correlation of the imaging parameters with the asphalt mixture performance.

Eyad Masad, Assistant Professor, Department of Civil and Environmental Engineering, Washington State University, Pullman, WA 99164-2910, Tel: 509-335 9147, Fax: 509-335-7632, Email: masad@wsu.edu; Joe W. Button, Head, Materials and Pavements Division, Texas Transportation Institute, The Texas A&M University System, College Station, TX 77843-3135, Tel: 409-845-9965, Fax: 409-845-0278, Email: J-Button@tamu.edu; and Tom Papagiannakis, Associate Professor, Department of Civil and Environmental Engineering, Washington State University, Pullman, WA 99164-2910, Tel: 509-335-4547, Fax: 509-335-7632, Email: mailto:masad@wsu.edu.

00-0693 "Uncompacted Voids and Particle Index Tests for Evaluating Coarse Aggregate"

Abstract: Coarse aggregate angularity and surface texture are aggregate properties specified under the SuperpaveTM mix design system. To control specification requirement, the fractured face count test is suggested. The use of a more objective tests was investigated. Uncompacted voids and index of aggregate particle shape and texture tests were studied to measure coarse aggregate angularity. The gradation of the sample has an obvious influence on both test results. Ways to separate the effect of gradation from aggregate angularity were studied. Viable options are testing a standard graded sample or computing a weighted average from tests of individual size fractions based on the gradation of the blend. When comparing aggregate sources, either option produces comparable evaluation but testing standard graded samples saves time. On the other hand, the weighted average is more appropriate for evaluating an aggregate blend. The index of aggregate particle shape and texture test and the uncompacted voids test provide comparable measures of coarse aggregate angularity and surface texture. Conclusions: Gradation has a significant effect on both particle index and uncompacted voids tests. Tests on graded samples are not as time consuming, and produce results comparable with weighted average values computed with values from individual size fractions. For relative comparison and evaluation of aggregate sources, tests on standard graded samples may be used. Either of two standard gradations for coarse aggregate may be used depending upon the availability of the size of particles in a source. For evaluation of aggregate blends to produce specific gradations for asphalt concrete, the use of composite values computed with individual size fractions is recommended to eliminate the influence of gradation during testing but to include gradation effects on composite values. Uncompacted voids and particle index are highly correlated and provide comparable measures of coarse aggregate particle shape, angularity and surface texture.

M. Shabbir Hossain, Frazier Parker, Jr. and Prithvi S. Kandhal, Auburn University, Auburn, AL 36849, Tel: 334-844-6284, Fax: 334-844-6290. Email: fparker@eng.auburn.edu.

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9. Pavement Management and Rehabilitation

00-0142 "Evaluation of Concrete Pavement Rehabilitation Techniques on I – 65"

Abstract: Construction of hot mix asphalt (HMA) overlays on top of old concrete pavements is the most common concrete pavement rehabilitation strategy. These overlays, however, are usually subject to reflection cracking related to the movement of the old concrete slab. In addition, these overlays may also be vulnerable to rutting when subjected to large volumes of heavy truck traffic. Concrete overlays have the advantage of being rut resistant compared to HMA overlays. However, the current national experience of the performance of these overlays is still relatively limited compared to HMA overlays. In addition, doubts are often raised about the cost effectiveness of these overlays, the ease of their rehabilitation at the end of their design life and the period of time required to close the road to traffic for ongoing and post construction operations. This paper presents an evaluation of three concrete pavement rehabilitation techniques employed on interstate highway I – 65; 190 mm (7.5 inches) of fiber modified HMA overlay on top of cracked and seated old concrete pavement, 330 mm (13 inches) of HMA overlay on top of rubblized old concrete pavement, and 305 mm (12inches) unbonded concrete overlay on top of 30 mm intermediate HMA layer on top of old concrete pavement. Performance of these rehabilitation techniques is also assessed in view with that of restoration (no overlay) techniques applied in 1985 on the same highway segment. It was concluded that all rehabilitation techniques performed satisfactorily. "Unbonded concrete overlay" segment exhibited the best performance in reflection cracks elimination, structural capacity and skid resistance. "Rubblized" segment exhibited the best performance in ride quality and uniformity of structural capacity. Life cycle cost analysis suggested that the " unbonded concrete overlay" was the most cost-effective segment. However, it was "a very close call."

Sedat Gulen, PE and A. Samy Noureldin, Ph.D., INDOT , Research Division, 1205 Montgomery Street - P.O. Box 2279, West Lafayette, Indiana 47906. Tel. 765-463-1521, Fax. 765-497-1665, snoureldin@indot.state.in.us.

00-0495 "Pavement Rehabilitation Selection Based on FWD Data Mechanistic Analysis and Field Diagnosis – Virginia Experience"

Abstract: This paper presents the effectiveness of using the field diagnosis and FWD mechanistic analysis in reducing a 65-km (40-mile) segment of asphalt pavement to project level segments and selecting a cost effective rehabilitation strategy. A mechanistic based analysis was performed on the deflection basins measured from I-85, Virginia, to backcalculate the layer moduli. The 65-km (40-mile) segment was divided into structurally homogeneous sections based on the backcalculated layer moduli. The data of each homogeneous section was further analyzed to assess the in-situ structural capacity, to identify weak layers, to estimate the remaining structural life and to determine the current and future rehabilitation needs. It was found that some sections have almost no remaining structural life, while others have remaining structural life of more than 10 years. Results of the study indicated that there are two problems contributed to the pavement failure of this project, poor performance of the Cement Treated Aggregate (CTA) layer and lack of subdrainage. The CTA layer was found to have significantly lower in-situ structural capacity, which is related to the high percentage of fines in the aggregate before stabilization (out of specifications) and to the low cement content. Also, the Soil Cement (SC) layer was found to be more cost-effective than the CTA layer, for this particular project. A comparison was made between the FWD/field diagnosis rehabilitation program and a visual inspection rehabilitation program. Results of the comparison indicated that the visual inspection rehabilitation program resulted in selecting thicker overlays for some of the project sections (overdesigned) and thinner overlays for the other sections (underdesigned). It is estimated that the difference between the FWD/field diagnosis rehabilitation program and the visual inspection rehabilitation program for the overdesigned sections is in the range of 45% of the construction cost (savings). Life Cycle Cost Analysis (LCCA) was performed to quantify the difference between the two rehabilitation programs for the underdesigned sections. Results of the LCCA indicated that the FWD/field diagnosis rehabilitation program would result in 26% and 42% reduction in the construction cost and user delay cost, respectively. The following were concluded from this study: Dividing long pavement segments into structurally homogeneous sections allows more cost-effective rehabilitation strategies. The FWD analysis provides an excellent, efficient tool for evaluating the structural performance of pavements. Although FWD testing reduces the amount of destructive testing, successful FWD analysis cannot be performed without an adequate field diagnosis program. Combining the FWD analysis with an adequate field diagnosis program leads to better understanding of pavement performance, and hence to more accurate and cost-effective rehabilitation strategies.

Sameh Zaghloul, Ph.D., P.E. Stantec Consulting Ltd., 152 Main St., Cambridge, Ontario, N1R 6R1, Canada, Tel: 519-622-3005, Fax: 519-622-2580, Email: szaghloul@stantec.com; and Mohamed Elfino, Ph.D., P.E., Pavement Design and Evaluation, Virginia Department of Transportation, 1401 East Broad St., Richmond, Virginia, 23219, Tel: 804-328-3173, Fax: 804-328-3136, Email: elfino_mk@vdot.state.va.us.

00-1283 "Estimation of Lives of Mill-and-Inlay Rehabilitation Strategies"

Abstract: The Kansas Department of Transportation (KDOT) and the Kansas Turnpike Authority (KTA) routinely mill the surfaces of some asphalt concrete pavements before inlaying as part of the substantial maintenance program. In selecting this strategy, no "life" is assigned due to a lack of methodologies to estimate lives of such strategies. In most cases, the

milling depth is selected based on the rule-of-thumb or experience of the agency for a specific surface distress, such as rutting or transverse cracking, rather than on any engineering analysis. In this paper, the functional and structural lives of such mill-and-inlay strategies were analyzed for seven different routes of KDOT and KTA. All test sections were tested with the Falling Weight Deflectometer (FWD) at 15 m to 30 m (50 to 100 ft) intervals before milling, after milling, and after inlaying. Fatigue tests were conducted on the beams sawn from four test sections on three routes. Fatigue distress models and rational transfer factors were found through the analysis of fatigue test results, deflection data, and historical traffic data to estimate the fatigue damage, functional performance, and rutting susceptibility of the mill-and-inlaid pavements. Conclusion: The results show that the "life" of a mill-and-inlay strategy is mostly controlled by serviceability. However, the strategy may reduce the fatigue life of the pavements with low traffic volumes. For high traffic pavements, an optimal mill-and-inlay depth based on fatigue can be found. Cost-effectiveness of the mill-and-inlay strategy is higher for pavements with high traffic volumes. The strategy did not appear to be susceptible to rutting nor did it appear to cause any damage to the existing pavement layers.

Zhong Wu, Mustaque Hossain and Andrew Gisi, Dept. of Civil Engineering, Kansas State University, Manhattan, KS 66506, Tel: 785-532 -1576, Fax: 785-532-7717, Email: mustak@ksu.edu.

00-1327 "Cost-Effectiveness of Reflective Crack Control Treatments In Illinois"

Abstract: The Illinois Department of Transportation (IDOT) spends two million dollars annually on reflective crack control treatments; however, their cost-effectiveness has never before been reliably determined. This study evaluated the cost-effectiveness of IDOT reflective crack control system "A", which consists of a non-woven, polypropylene paving fabric, placed either in strips longitudinally over lane-widening joints or over the entire pavement ("area" treatment). The study was limited to projects constructed originally as rigid pavements, and subsequently rehabilitated with one or more bituminous overlays. Performance of fifty-two projects across Illinois was assessed through crack mapping and from distress and serviceability data in IDOTs condition rating survey (CRS) database. Comparisons of measured reflective cracking in treated and control sections revealed that system "A" retarded longitudinal reflective widening crack development, but did not significantly retard transverse reflective cracking, which agrees with earlier studies. However, both strip and area applications of these fabric treatments appeared to improve overall pavement serviceability, and were estimated to increase rehabilitation life spans by 1.1 and 3.6 years, respectively. Reduction in life cycle costs were estimated to be 4.4 and 6.2 percent when placed in medium and large quantities, respectively, and at a break-even level for small quantities. However, the difference in life-cycle costs of strip- or area-treated projects relative to untreated projects (those not receiving crack control) was found to be statistically insignificant. Limited permeability testing of field cores taken on severely distressed transverse joints suggested that waterproofing benefits could exist even after crack reflection. This was consistent with the observation that, while serviceability was generally improved with area treatment, crack reflection was not retarded relative to untreated areas. IDOT has experimented with the use of a higher strength material called ISAC (interlayer stress absorbing composite) over the past five years. ISAC, which was originally developed at the University of Illinois, appears to substantially retard reflective cracking. However, future studies will be needed to evaluate its overall cost-effectiveness.

William G. Buttlar, Ph.D., P.E., and Diyar Bozkurt, M.S.C.E, Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Advanced Transportation Research and Engineering Laboratory (ATREL), 205 N. Mathews Avenue, 1212 Newmark Laboratory, Urbana, IL 61801, Tel: 217-333-5966, Fax: 217-333-1924, buttlar@uiuc.edu.

00-0336 "A Structured Approach to Managing The Quality of Pavement Distress Data: Virginia DOT Experience"

Abstract: VDOT has examined and improved the quality of condition data to carry out pavement performance analysis and multi-year work planning. In 1995 the agency changed the way it gathered pavement condition data, moving from windshield type surveys to using automated condition survey equipment. In 1997 the agency acquired the staff to examine these data and respond to the concerns of personnel that the data were inconsistent and not representative of actual conditions. It was shown in 1998 that standardization of test methods and the calibration of equipment for roughness measurement yielded data of much higher quality than previous years. Conclusions: 1. VDOT’s experience with distress data proves that distress data quality can suffer from serious problems. 2. VDOT’s conclusion after the quality audit was that data quality problems were caused by ill-defined requirements as well as large-scale precision and bias problems in the data collection equipment and methods. 3. Redesigning the data collection effort requires a clear vision of needs. In VDOT’s case, this involved the realization that data needed to be sufficiently accurate to allow the modeling of multi-year pavement deterioration. This resulted in stringent quality requirements. In conclusion, re-engineering a flawed data collection effort is a complex exercise. It involves a rethinking of requirements, development of detailed specifications and procedures, an in-depth statistical analysis of individual data elements and an understanding of data collection equipment limitations. Most importantly, this re-engineering effort involves paying attention to the data collection process by building controls at critical junctures during the project in order to deliver a quality data product in time and on budget.

Charles D. Larson, Naveed Sami, and David R. Luhr, VDOT, 1401 East Broad Street, Richmond, Va., 23219, Tel: 804-328-3026 Email: larson_cd@vdot.state.va.us.

00-0345 "Investigation of the Relationship Between Roughness and Pavement Surface Distress based on the WesTrack Experiment"

Abstract: Modern pavement rehabilitation and design methodologies require an adequate evaluation of the functional capacity of pavements. A key component of this functional capacity is the roughness of the pavement. Pavement roughness measurements were conducted at regular intervals during the application of approximately 5 million equivalent single axle loads (ESALs) at the WesTrack project, a full scale accelerated pavement loading facility, located near Reno, Nevada. The objective of this paper is to present the results of an investigation into the relationship between pavement roughness and pavement surface distress using WesTrack data. Using a sample population of 317 observations, a relationship was found between the roughness , using the International Roughness Index (IRI), the initial IRI, percentage of fatigue cracking, and average rut depth. A test of the relationship with data collected as a part of the Long Term Pavement Performance Project (LTPP) indicates favorable results.

Conclusions: This paper provides a unique relationship of the International Roughness Index as a function of initial IRI and distress. An R-squared value of 0.71 and average error of 0.107 m/km indicates the WesTrack relationship correlates well with the WesTrack collected data. This relationship is highly dependent on initial IRI, which agrees with the findings of recent research into the parameters influencing pavement roughness. The WesTrack relationship provides favorable results in a test with LTPP field data. The average error of all the pavement sections was 13.9 percent. This is a promising relation that needs to be further tested as additional data becomes available.

Joseph Mactutis, Sirous Alavi, and Weston Ott, Nichols Consulting Engineers, 1885 S. Arlington Ave., Suite 111, Reno, NV 89509, Tel: 775-329-4955, Fax: 775-329-5098, Email: joseph@nce.reno.nv.us.

00-1258 "Evaluation of the Accuracy of Surface Profilers"

Abstract: The Texas Department of Transportation (TxDOT) is implementing smoothness specifications based on profilograph testing as part of its construction quality control/quality assurance (QC/QA) program. Most tests are presently conducted using automated, California-type profilographs in which the equipment is pushed over a prescribed wheelpath. It appears that smoothness specifications will continue to be based on the profilograph, at least for the short term. However, in view of advances in profiling technology, it becomes prudent to investigate other methods of measuring surface profiles and develop smoothness specifications based on profilers that offer greater accuracy and higher production rates. In pursuit of its goal of providing smooth pavements, TxDOT initiated a research project with the Texas Transportation Institute (TTI) to develop a smoothness specification for asphalt concrete overlays based on the new generation of pavement profilers that offer greater accuracy in profile measurement relative to the profilographs presently used in construction projects. Among other things, this research project evaluated a number of profile measuring devices to establish the availability of equipment for implementing a new profile-based smoothness specification in Texas. This evaluation showed that lightweight profilers provide a basis for developing and implementing smoothness specifications that are based on surface profile. Since surface smoothness is commonly monitored using inertial profilers in pavement condition surveys conducted for pavement management, having the initial profile allows highway agencies to tie the as-built smoothness to the rest of the performance history, and thus maintain a consistent historical record of surface smoothness throughout the pavement life-cycle.

Emmanuel Fernando, PhD., P.E., Associate Research Engineer, Texas Transportation Institute, Texas A&M University, College Station, Texas 77843-3135, Tel: 409-845-3641, Fax: 409-845-0278, Email: e-fernando@tamu.edu.

00-1261 "Evaluation of Relationship Between Profilograph and Profile-Based Roughness Indices"

Abstract: The relationship between the profilograph profile index (PI) and the International Roughness Index (IRI) is evaluated. To accomplish this, profile data taken on 48 overlaid test sections were used in profilograph simulations to predict the profilograph response to the measured profiles. The profile indices determined were then correlated with IRIs computed from the profile data to evaluate relationships between these roughness statistics. The results show that the profile index based on the null blanking band is more strongly related to the IRI than the corresponding index determined using the 5 mm blanking band. In view of the general acceptance of IRI as a statistic for establishing surface smoothness based on profiles, the results suggest that a profilograph specification based on the null blanking band is preferable to a similar specification based on the 5 mm blanking band, which may mask certain components of roughness that are otherwise picked up if no blanking band is used. From another perspective, the results suggest that for agencies considering the development and implementation of a profile-based smoothness specification, the null blanking band PI may be useful as an interim specification, particularly for agencies with an existing specification based on the 5 mm blanking band. This appears to be a logical step in view of the availability of profilographs and experience with its use in many states. Because of this existing widespread use, a transition period may be necessary. Based on the results presented in this paper, switching from a 5 mm to a null blanking band should improve the evaluation of surface smoothness quality on construction projects while permitting contractors the continued use of their present equipment, at least for the short term. The relationship developed between IRI and null blanking band PI may be used in revising the existing specification so that the acceptance schedule is tied to the profile statistic, IRI, which has been found to strongly correlate with pavement ride quality.

Emmanuel Fernando, PhD., P.E., Associate Research Engineer, Texas Transportation Institute, Texas A&M University, College Station, Texas 77843-3135, Tel: 409-845-3641, Fax: 409-845-0278, Email: e-fernando@tamu.edu.

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10. Safety

00-0151 "Service Performance Evaluation of the BCT and MELT Guardrail Terminals in Iowa and North Carolina"

Abstract: Developing safe and effective guardrail terminals has been a high priority for roadside safety researchers for several decades. Numerous full-scale crash tests have been performed and many types of new terminals have been developed. This paper presents results for an in-service performance evaluation of two popular guardrail terminals, the breakaway cable terminal and the modified eccentric loader breakaway cable terminal. The data was collected in portions of Iowa and North Carolina during a 12-month data collection effort in 1997 and 1998. The collision performance was measured in terms of collision characteristics, occupant injury and barrier damage. The results of this study indicated that the MELT and BCT perform acceptably for the broad range of impact conditions and scenarios experienced in the field although neither system passed the most recent full-scale crash test and evaluation criteria. Proper installation and maintenance was found to be important in ensuring the correct performance of the terminal in an impact.

Malcolm H. Ray and Jeffery A. Hopp, Civil Environmental Engineering Department, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609-2280, Tel: 508-831-5340, Fax: 508-831-5808, Email: mhray@wpi.edu, WWW: http://www.wpi.edu/~mhray.

00-0388 "Transitions from Guardrail to Bridge Rail that Meet Safety Performance Requirements"

Abstract: Three guardrail-to-bridge rail transitions have been developed and subjected to full-scale crash tests. They are: (1) a nested W-beam with W-beam rubrail that transitions from a W-beam guardrail to a vertical concrete parapet bridge rail, (2) a nested thrie-beam that transitions from a W-beam guardrail to a tubular steel bridge rail and (3) a tubular steel transition that transitions from a weak-post box-beam guardrail to a tubular steel bridge rail. The nested W-beam and the tubular steel transitions were tested to and met the requirements of test level 3 of NCHRP Report 350. The nested thrie-beam transition was tested to and met the requirements of test level 4.

Eugene C. Buth, Wanda L. Menges, King K. Mak and Rodger P. Bligh, Texas Transportation Institute, Texas A&M University System, College Station, TX 77843-3135, Tel: 409-845-6159, Fax: 409-845-6107, Email: g-buth@tamu.edu.

00-0410 "Test Level Four Bridge Rails"

Abstract: This paper presents design details and results of full scale crash tests for three bridge rails that meet test level 4 of NCHRP Report 350. Designs of these rails are based on provisions of the AASHTO LRFD Bridge Specifications. Each of the bridge rails consists of structural steel tubing rail elements mounted on wide-flange posts. The Alaska Multi-State Bridge Rail was tested under a cooperative agreement sponsored by Alaska, Oregon, Washington, and North Dakota. The rail design is based on the existing Oregon Two-Tube Bridge Rail. Two versions of the Massachusetts S3-TL4 were studied. One version is mounted on a 1.5 m wide sidewalk with a 200 mm high curb face on the traffic edge of the sidewalk. The other version is mounted on a 200 mm high curb with the traffic face of the railing being flush with the face of the curb. The rails are generally stronger than many designs commonly used in the recent past. Results of full-scale crash tests demonstrated that all these bridge rails meet safety performance requirements of NCHRP Report 350.

C. Eugene Buth, Wanda L. Menges, and William F. Williams,Texas Transportation Institute, The Texas A&M University System, College Station, Tx 77843-3135, Tel: 409-845-6375, Fax: 409-845-6107, Email: g-buth@tamu.edu.

00-0525 "Comparison of the Impact Performance of the G4(1w) and G4(2w) Guardrail Systems Under NCHRP Report 350 Test 3-11 Conditions"

Abstract: Several types of strong-post W-beam guardrails are used in the United States. Usually the only difference between one type of strong-post W-beam guardrail and another is the choice of post and blockout types. This report compares the impact performance of two very similar

strong-post W-beam guardrails: the G4(2W) which uses a 150x200 mm wood post and the G4(1W) which uses a 200x200 mm wood post. While the G4(2W) is used in a number of states, the G4(1W) is now common only in the state of Iowa. Though the performance of the two guardrails have been presumed to be equivalent, only one full-scale crash test has ever been performed on the G4(1W) and that test was performed over 30 years ago using a now-obsolete test vehicle. The non-linear finite element analysis program LS-DYNA was used to evaluate the crashworthiness of the two guardrails. The G4(2W) guardrail model was validated with the results of a full-scale crash test. A model of the G4(1W) guardrail system was then developed and the two guardrails were compared with respect to deflection, vehicle redirection and occupant risk factors. A quantitative comparison of the two impacts was performed using standard techniques. The results of the analysis indicate that the G4(1W) and G4(2W) perform similarly in collisions and they both satisfy the requirements of NCHRP Report 350 for the test 3-11 conditions.

Chuck A. Plaxico, Tel: 508-831-5598, Email: cplaxico@wpi.edu, Malcolm H. Ray, Tel: 508-831-5340, Email: mhray@wpi.edu, and Kamarajugadda Hiranmayee, Email: hiranmay@wpi.edu, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, Fax: 508-831-5808.

00-0598 "A Long-Span Guardrail System for Culvert Applications"

Abstract: A long-span guardrail for use over low-fill culverts was developed and successfully crash tested. The guardrail system was configured with 30.48 m of nested 12-gauge W-beam rail and centered about a 7.62-m long unsupported span. The nested W-beam rail was supported by sixteen W152x13.4 steel posts and six standard CRT posts, each with two 150-mm wide x 200-mm deep x 360-mm long wood blockouts. Each post measured 1,830-mm long. Post spacings were 1,905-mm on center except for the 7.62-m spacing between the two CRT posts surrounding the long span. The research study included computer simulation modeling with BARRIER VII and full-scale vehicle crash testing, using :-ton pickup trucks in accordance with the TL-3 requirements specified in NCHRP Report No. 350, Recommended Procedures for the Safety Performance Evaluation of High Features. Three full-scale vehicle crash tests were performed. The first test was unsuccessful due to severe vehicle penetration into the guardrail system. This vehicle penetration occurred as a result of a loss of rail tensile capacity during vehicle redirection, due to the failure of the swagged fitting on the cable anchor assembly. A second test was performed on the same design which contained a new cable anchor assembly. During vehicle redirection, the pickup truck rolled over, and the test was judged to be a failure. The long-span system was subsequently redesigned to incorporate double blockouts on the CRT posts and crash tested again. Following the successful third test, the long-span guardrail system was determined to be acceptable according to the TL-3 criteria found in NCHRP Report No. 350 and is a suitable design for use on Federal-aid highways.

Ronald Faller, Dean Sicking, Karla Polivka, John Rohde, and Robert Bielenberg, Midwest Roadside Safety Facility, University of Nebraska-Lincoln, 1901 Y St., Building C, Lincoln, Nebraska 68588-0601, Phone: 402-472-6864, Fax: 402-472-0506, Email: rfaller1@unl.edu.

00-1528 "Safety Effectiveness of Upgrading Guardrail Terminals to Report 350 Standards"

Abstract: Developing safe and effective guardrail terminals has been a high priority for roadside safety researchers for several decades. Numerous full-scale crash tests have been performed and many types of new terminals have been developed . In recent years the Federal Highway Administration formalized the evaluation and certification process for roadside safety hardware with the net result that all guardrail terminals to be used on the National Highway System must now satisfy the full-scale crash test and evaluation requirements of National Cooperative Highway Research Program Report 350. While there is no doubt that newer guardrail terminals are characterized by better full-scale crash test performance, it is less clear how relevant such improvement is to a reduction in serious and fatal injuries in real-world guardrail terminal collisions. The purpose of this paper is to examine several in-service performance evaluations of guardrail terminals and determine if upgrading guardrail terminals to NCHRP Report 350 standards can be expected to result in a reduction in serious and fatal injury accidents. An examination of actual collisions in Iowa, North Carolina and Ohio involving BCT, MELT and ET-2000 terminals indicated that there was no statistically significant difference between the safety performance of these three devices. The sample sizes were small so these data should be considered preliminary but the data suggest that upgrading to a Report 350 guardrail terminal may not result in a noticeable decrease in severe or fatal injury collisions.

Malcolm H. Ray, Civil and Environmental Engineering Department, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609-2280, Tel: 508-831-5340, Fax: 508-831-5808, Email: mhray@wpi.edu.

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11. Soils, Geology, and Foundations

00-0604 "Lime Requirement for Stabilization"
C. D. F. Rogers, S. Glendinning

Abstract: Lime is used in construction as a rapid and economic method of improving the strength and stiffness characteristics of clay soils. For economic design, an engineer must know how much lime is required to initiate the required improvements. If lime stabilization is to be compared with alternative solutions in the early stages of a project, it must be possible to make this assessment rapidly and with the minimum expenditure on additional specialist testing. The ASTM Standard (Test Method for Determining Stabilization Ability of Lime (MDSAL), (1)) aims to determine the quantity of lime required for stabilization using simple methodology to generate results quickly. Additional, much lengthier testing is recommended to verify the lime requirement if lime is considered feasible following MSDAL testing. Problems have been found in the execution of the test and interpretation of results, resulting in inconsistency in the lime quantities calculated. This inconsistency could lead to substantial differences to the estimated cost of the overall scheme, and possibly the unwarranted rejection of lime stabilization as a potential solution. This paper reviews the methodology of the MDSAL test through practical experimentation and makes recommendations for its future use. The sensitivity of the test to changes in lime quality, volume of water added and temperature is examined. It is shown that, although extremely sensitive to changes in these parameters, a revised interpretation of test data means that a reliable and consistent result can be achieved. The scientific basis for this revised interpretation is also demonstrated. Conclusions: The results produced from the MDSAL are sensitive to changes in lime quality, temperature and water addition. However, the shape of the lime addition-pH plots produced from the MDSAL results is not sensitive to alterations in the above parameters. It is recommended that a modified graphical interpretation of the MDSAL data be adopted in order to produce more consistent and reliable results. The results of the test interpreted in this way should be used as an indicator of the minimum amount of lime required and should be verified using performance testing under the conditions expected on site.

C. D. F. Rogers, BSc, PhD, CEng, MICE, MIHT, School of Civil Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom, Tel: +44 121 414 5066, Fax: +44 121 414 3675, Email: c.d.f.rogers@bham.ac.uk; and S. Glendinning, BSc, PhD., Department of Civil Engineering, Drummond Building, University of Newcastle-upon-Tyne, Newcastle-upon-Tyne NE1 7RU, United Kingdom, Tel: +44 191 222 6612, Fax: +44 191 222 6613, Email: stephanie.glendinning@ncl.ac.uk.

00-0608 "Incorporating Subgrade Lime Stabilization into Pavement Design"

Abstract: The benefits of subgrade lime stabilization are incorporated, for the first time, into the pavement design of a major interstate highway in Pennsylvania. The project comprises widening and complete reconstruction of 21 km of the Pennsylvania Turnpike in Somerset County. Field explorations indicated that the subgrade is fairly homogeneous and consists primarily of medium to stiff clayey soils. To safeguard against potential softening due to rain, lime modification has been traditionally utilized as a construction expedience for highway projects with clayey subgrade. Such an approach, however, does not take advantage of the added strength of the lime-stabilized subgrade in pavement design. Lime improves the strength of clay by three mechanisms: hydration, flocculation, and cementation. The first and second mechanisms occur almost immediately upon introducing the lime and they are the focus of this paper; the third is a prolonged effect. Laboratory tests were performed to accurately capture the immediate benefits of lime stabilization for design. Both treated and natural clayey samples were subjected to resilient modulus and California bearing ratio testing. The lime-treated specimens were not allowed to cure to prevent cementation from developing. The most remarkable conclusion is that lime stabilization surpasses its traditional highway utilization of merely improving the workability of clayey subgrades. Even neglecting cementation, lime improves the pavement and significantly reduces its cost by increasing the strength of the subgrade. Its immediate benefits are easily captured through laboratory testing on uncured soil-lime specimens to determine the modified strength properties for design. Laboratory resilient modulus and California bearing ratio testing on lime-treated specimens show an immediate increase in stiffness/strength by a factor of 4 to 5 without curing.

Bashar S. Qubain, Eric J. Seksinsky, and Jianchao Li, Valley Forge Laboratories, Inc., 6 Berkeley Road, Devon, PA 19333, Tel.: 610-688-8517, Fax: 610-688-8143, Email: bqubain@valleyforgelabs.com.

00-0665 "Superjet Grouting: A New Technology for In Situ Soil Improvement"

Abstract: The New Jersey Department of Transportation solicited a Request For Proposal for a design-construct bid to extend the Atlantic City Expressway to the Marina District and Brigantine. This would service a developing area for casino construction as well as greatly improve access to the beachfront towns north of Atlantic City. The preliminary document required an approximate 0.8 km (half mile) of four-lane roadway to go underground to eliminate traffic noise and pass under Route 30. The prime and specialist contractors, in concert with intuitive engineering support, developed an in situ installation of a subgrade bottom strut bracing system for a cut-and-cover tunnel installation, using the new system of SuperJet grouting.. This paper presents this new technology, the method of installation, difficulties overcome, and the QA/QC elements of this portion of the project. Future applications will also be proposed. Summary: SuperJet grouting was able to provide a continuous, horizontal brace and horizontal groundwater barrier for the pump station, a strut and wale system to support the base of the

tunnel excavation, and a vertical groundwater barrier to permit dry, sectional excavation for the tunnel. Over 1,000, 4-m (13 ft) diameter soilcrete columns were constructed for the 670-m (2200-ft), braced length of the cut-and-cover tunnel. Preconstruction testing provided confidence in the new technology, and quality control sampling and testing provided confidence that construction work met and exceeded design requirements.

George K. Burke, Kenneth R. Chadwick, Hayward Baker Inc., 1130 Annapolis Road, Suite 202, Odenton, MD 21113, Tel: 410-551-8200, Fax: 410-551-1900, gkburke@haywardbaker.com, krchadwick@haywardbaker.com; and David M. Cacoilo, Mueser Rutledge Consulting Engineers, 708 Third Ave., New York, NY 10017, Tel: 212-490-7110, Fax: 212-953-5828, cacoilo@mrce.com.

00-0687 "European Research into Granular Material for Pavement Bases and Sub-bases"

Abstract: After a brief review of the recent history of research into the behavior of granular material for pavement bases and sub-bases by European researchers, and a reasonably comprehensive list of specialist European publications, the paper describes two trans-national European research projects active in the area and the results obtained from them. These results are used to illustrate the 'state-of-practice' as compared to the 'state-of-the-art' from a laboratory perspective and are placed within the setting of a broad picture of national research within Europe. Comments are made as to the direction of research and its implementation within Europe, those areas which will continue to be problematic and the findings and strategies which suggest better-practice for non-European users. The use of the repeated load triaxial test is an important aspect of the research work described. Although the test is shown to have limitations for practical purposes, it illustrates the nature of material behaviour which may be expected in-situ. It is concluded that European research has progressed a long way in bringing a fundamental engineering understanding to granular material pavement layer technology, but that there remain issues of in-situ assessment, analytical methods and variability of in-situ condition which hinder full application of our understanding of granular materials into an analytical description of pavement bases and sub-bases. A substantial reference list is included to help readers locate European research findings in the topic area. Discussion is included on the advantages offered by adopting a mixture of direct research funding of a specific technical project and the provision of linked travel-only (marginal) costs to a wider group, which has access to the findings of the directly funded project, as this encourages technology transfer and the beneficial direction of the research study.

Andrew R. Dawson, School of Civil Engineering, University Park, Nottingham, NG7 2RD, UK, Email: andrew.dawson@nottingham.ac.uk.

00-0722 "Dutch Design Manual for Light-Weight Pavements with EPS Geofoam"

Abstract: The use of Expanded PolyStyrene (EPS) Geofoam instead of traditional "heavy" sand for pavement sub-base can reduce or even eliminate the additional load on the subsoil, thus decrease or eliminate the settlement of pavement structures on a compressible subsoil. The experiences with EPS Geofoam are very positive but a uniform design procedure does not yet exist for this type of structure. Optimization of the existing EPS pavement design guidelines and their improvement has demanded materials research on EPS, the use of three-dimensional finite element pavement models and in situ full-scale measurement. Extensive materials research provided data for the stress-strain response of EPS under representative loading and environmental conditions. 3-D modelling enabled critical evaluation of existing design methodologies by analyzing pavements with different roadbases, different EPS types and different asphalt thicknesses. In situ measurements by means of built-in strain transducers in asphalt provided data for verification of the 3-D modelling. Furthermore, evaluation and monitoring of Dutch projects with EPS geofoam has been carried out to define problematic aspects from practical point of view. Based on the research findings the current Dutch design guidelines have been revised and optimized. In order to make this knowledge easily accessible an official Dutch Design Manual for Light-weight Pavements with EPS Geofoam has been composed under the auspices of the Center for Research and Contract Standardization in Civil and Traffic Engineering (C.R.O.W). The outlines of the manual are presented.

Milan Duškov, Grontmij V&I bv, P.O. Box 203, 3730 AE De Bilt, The Netherlands, Tel: +31 30 2207 468, Fax: +31 30 2213 493, Email: milan.duskov@grontmij.nl.

00-1315 "Stabilization of an Embankment Slope with Geofoam"

Abstract: A case history is presented describing the use of expanded polystyrene (EPS) blocks, generically known as geofoam, to treat an unstable roadway embankment slope involving clayey soils. The selection of the geofoam treatment was based upon its constructability, and least impact on both the environment and adjacent homeowners. The site subsurface conditions, engineering properties of EPS, design analysis and construction phases are reviewed. Potential traffic safety problems associated with differential icing of roadways from the presence of geofoam blocks beneath pavements was minimized by using a thicker subbase layer in the geofoam-treated area. Data from an instrumentation program consisting of an inclinometer, extensometers and thermistors are presented. Pavement temperature readings collected from areas with and without geofoam treatment are compared to investigate potential differential icing on the roadway. Conclusions: Use of geofoam to reduce the driving force of a slope has proved effective in stabilizing the slope at the New York State Rte. 23A site. No slope movement has occurred since the treatment was completed in 1996. The issue of differential icing has been addressed and no such a phenomenon has occurred on the roadway. The treated embankment area continues to be monitored both for slope movement and temperature variations of the pavement structure at various locations.

Walter S. Jutkofsky, J. Teh Sung and Dawit Negussey, New York State, Department of Transportation, Bldg 7, State Campus, 1220 Washington Ave., Albany, NY, 12232-0002, Tel: 518-457-4784, Fax: 518-457-8000, Email: Tsung@gw.dot.state.ny.us.

00-1408 "Liquefaction Mitigation Using Stone Columns Around Deep Foundations: Full Scale Test Results"

Abstract: The results presented in this paper were developed as part of a larger project analyzing the behavior of full-scale laterally loaded piles in liquefied soil, the first full-scale testing of its kind. This paper presents the results of a series of full-scale tests performed on deep foundations in liquefiable sand, both before and after ground improvement, where controlled blasting was used to liquefy the soil surrounding the foundations. Data was collected showing the behavior of laterally loaded piles before and after liquefaction. After the installation of stone columns, the tests were repeated. Based on the results of these tests, it can be concluded that the installation of stone columns can significantly increase the density of the improved ground as indicated by the cone penetration test. Furthermore, it was found that the stone column installation limited the excess pore pressure increase from the controlled blasting and substantially increased the rate of excess pore pressure dissipation. Finally, the stone columns were found to significantly increase the stiffness of the foundation system, by more than 2.5 to 3.5 times that in the liquefied soil. This study provides some of the first full-scale quantitative results on the improvement of foundation performance due to stone columns in a liquefiable deposit.

Scott Ashford, Kyle Rollins, Samuel Bradford, Juan Baez, Department of Structural Engineering, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0085, Tel: 858-822-0431, Fax: 858-822-2260, Email: sashford@ucsd.edu.

00-0759 "Pre-design Foundation Load Test Program for the US 17 (Wilmington) Bypass over the Northeast Cape Fear River"

Abstract: The North Carolina Department of Transportation is presently conducting a pre-design foundation load test for a new bridge over the Northeast Cape Fear River near Wilmington, North Carolina. The primary purpose of the load test program is to determine whether concrete piles can penetrate a very dense and cemented sand layer and what side friction and tip bearing capacities should be used for the design of the drilled piers. Significant cost savings could be realized if pile foundations could support the approach spans of the bridge instead of drilled piers. To determine this, three concrete piles will be installed 30 meters into the ground. Significant cost savings can also be realized by making a more accurate determination of the drilled pier capacities. To determine this, the side friction and tip bearing capacities of the dense Peedee sands and the underlying hard marine clays will be determined with Osterberg Cell tests on two 2130 mm dia. drilled piers. The different subsurface layers (muck, alluvial sands and Peedee sands) will also be tested laterally with both static and statnamic testing to assist in the foundation design. The load test program incorporates a NCHRP research program on pile groups. The program includes testing a reusable instrumented steel pile group and frame at various sites in various soil conditions around the U.S. This paper will describe the load test program results to date, the effect of the results on the foundation design and the construction, testing and instrumentation of the drilled piers. Conclusions: 1. The mini-SID and the SPT tests are reasonable, cost and time effective methods for inspecting a drilled pier excavation for cleanliness and end bearing, respectively, when the excavation can not be reasonably dewatered. 2. The skin friction values are highly dependent upon construction practice including slurry type, drilling methods and time of operation. Overreaming should only be considered as a last resort and a drilled pier excavation that has been open for a long time may result in a drilled pier with lower than expected capacities. Overreaming did not restore skin friction to the level it was when the sidewalls were first exposed for this project. 3. The Osterberg Cell test may not perform as planned and yield the information expected if the soils do not provide the reaction load required. Past experience and consultation in developing the O-cell load test plan is critical. 4. A pre-design foundation load test can save a substantial amount in the construction cost of the bridge as well as provide invaluable information for design and contract document preparation. In addition, the lessons learned during the construction of the load test program can lead to additional savings in the form of reduced claims and constructability problems during the actual bridge construction.

Scott Hidden, P.E. and Nariman Abar, P.E. North Carolina Department of Transportation, Design Services Unit, Soils and Foundation Section, 1020 Birch Ridge Drive, Raleigh, NC 27610, Tel: 919-250-4128, Fax: 919-250-4119, Email: shidden@dot.state.nc.us.

00-0950 "Techniques for Maintenance of Pavement Subsurface Drainage Systems"

Abstract: The decision to construct pavements with subsurface drainage must be accompanied by a solid commitment to regularly inspect and maintain them. Clogged, flooded, or improperly performing subsurface drainage systems not only negate the additional costs of installing these systems but may result in more damage than if no system was provided. The costs of providing routine inspections and maintenance are negligible compared to the costs of repairing the damage caused by poorly functioning subsurface drainage systems. Thus an agency should not incorporate subsurface drainage features if consistent maintenance cannot be assured over its design life. This paper identifies the effects of inadequate maintenance of subsurface drainage systems on pavement performance and presents guidelines and recommendations for performing inspection and maintenance activities. The recommendations presented are based on various inspection and maintenance procedures, techniques, and equipment that have been used successfully by State highway agencies.

Leslie Titus-Glover, Jagannath Mallela, and Michael I. Darter, ERES Consultants, Division of Applied Research Associates, Inc., 505 W. University Avenue, Champaign, IL 61820, Email: Ltitusglover@ara.com.

00-0994 "Considerations for Providing Subsurface Drainage in Jointed Concrete Pavements"

Abstract: This paper discusses the design considerations for pavement subsurface drainage in new or reconstructed jointed concrete pavements. Considerations are outlined for all the components of a permeable base system (permeable bases, separator layers, edgedrains, and outlets). The topics of discussion—including guidelines for determining the need for drainage, components of a permeable base system, hydraulic design of permeable base systems, structural design of permeable bases and separator layers, and economic considerations of providing drainage—are arranged to provide a comprehensive picture of the subject area. A synthesis of information is presented for areas that have established procedures, such as hydraulic design of permeable bases. New ideas and concepts are proposed in areas where there is a lack of information or a clear consensus among researchers. Conclusions: Issues concerning the inclusion of permeable base systems in jointed pavements were discussed. The information presented includes both current practices and new concepts. New methodologies were proposed in the areas of assessment of drainage needs, structural design of permeable bases, and considerations for separator layers. Economic considerations of providing a permeable base system were also discussed briefly. For the structural design of jointed concrete pavements with permeable bases, the authors highlighted the advantages of using the procedure outlined in the AASHTO 1998 Supplemental Guide. This procedure does not use an empirical drainage coefficient in the design, thus eliminating a lot of subjectivity. However, because the drainage coefficient is used in the faulting model to check the performance, the authors presented an improved methodology to determine this coefficient. It is recommended that any future development of mechanistic-based pavement design procedures should directly account for the drainage conditions in the pavement by taking into account performance data available from the LTPP database.

Jagannath Mallela, Leslie Titus-Glover, and Michael I. Darter, ERES Consultants, A Division of ARA, Inc., 505 W. University Ave., Champaign, IL 61820, Tel: 217-356-4500, Fax: 217-356-3088.

00-1313 "Field Evaluation of Geocell Use in Flexible Pavements"

Abstract: Wheel rutting in excess of 100mm occurred within seven days after the reconstruction of a section of route 30, an urban roadway which has a high average daily traffic (ADT), in Delaware County, Pennsylvania. The road was reconstructed on a weak subgrade and soil tests produced California Bearing Ratio (CBR) values between 1.5 – 6.5%. A geocell confinement system was used in the subbase to stabilize the subgrade and solve this problem. The geocell used on this project is constructed from high-density polyethylene. Each geocell panel is fabricated using 60 strips that are 3.3-m long and 100-mm thick. The panels are 2.4m x 6.1m when expanded and create a honeycomb pattern cellular confinement system. The geocell system was used in combination with other geosynthetics (geogrid and geotextiles). The findings indicated that the geocell used in this project performed very favorably. The roadway has not shown any pavement distress (alligator cracking, rutting, etc.) during the three-year evaluation period. Falling weight deflectometer (FWD) data was collected initially after construction was completed then annually for two years. The FWD measurements were used to calculate the surface modulus and backcalculate the resilient modulus of the subgrade based on known thicknesses and reasonably assumed resilient moduli of pavement layers based on material testing and field experience. Although, it was difficult to isolate the effect of geocell confinement system as it has been used in combination with geogrid and/or geotextile in all cases. However, one can conclude that in sections where 100-mm-thick geocells were used, the resilient modulus of the aggregate layer has increased by almost twofold due to the material confinement. In addition, a geotextile-geocell combination was found to be more effective than a geogrid-geotextile combination. The geotextile-geocell combination may provide a significant improvement when used on top of weak subgrade of heavily trafficked pavement due to the aggregate confinement provided by the geocell and the subgrade/subbase separation provided by the geotextile.

Imad L. Al-Qadi, Professor, The Via Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, 200 Patton Hall, Blacksburg, VA 24061-0105, Tel: 540-231-5262, Fax: 540-231-7532, Email: alqadi@vt.edu; and John J. Hughes, Research Project Manager, Pennsylvania Department of Transportation, 1118 State Street, Harrisburg, PA 17120, Tel: 717-787-3584, Fax: 717-783-5955, Email: jjhughes51@hotmail.com.

00-0892 "Five-Year Field Study of the Water Quality Effects of Tire Shreds Placed Above the Water Table"

Abstract: A field trial was constructed beneath a secondary state highway in North Yarmouth, Maine to investigate the water quality effects of tire shred fills placed above the groundwater table. Samples were collected in three 3-m square geomembrane lined basins located beneath the shoulder of the road. Two of the basins are overlain by 0.61 m of tire shreds with a 75-mm maximum size topped by 0.72 to 1.37 m of granular soil. The third basin serves as a control and is overlain only by 0.72 m of granular soil. Quarterly samples for inorganic constituents were taken from January, 1994 through June, 1999. Samples were tested for metals with primary (health-based) drinking water standards and secondary (aesthetic-based) drinking water standards. In addition, samples were taken for volatile and semivolatile organic compounds on three dates. Conclusions: No evidence was found that tire shreds increased the concentration of metals with a primary drinking water standard including: barium (Ba), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), and selenium (Se) or the following substances with secondary drinking water standards: aluminum (Al), chloride (Cl-), sulfate (SO4), and zinc (Zn). There was some evidence that tire shreds could increase the levels of iron (Fe) and exceed the secondary drinking water standard under some conditions. Tire shreds increase the levels of manganese (Mn), which has a secondary drinking water standard. It is likely that the levels will exceed this standard. However, manganese is of aesthetic concern only. Negligible levels of organics were measured. Overall, tire shreds placed above the water table had a negligible impact on water quality for the near neutral pH conditions found at the North Yarmouth Field Trial.

Dana N. Humphrey, Ph.D., P.E., Dept. of Civil and Environmental Engineering, University of Maine, 5711 Boardman Hall, Orono, ME 04469-5711, Tel: 207-581-2176, Fax: 207-581-3888, Email: dana.humphrey@umit.maine.edu; and Lynn E. Katz, Ph.D., Civil Engineering Department, University of Texas at Austin, Room EJC 8.614, Austin, TX 78712-1076; Tel.: 512-471-4244, Email: lynnkatz@mail.utexas.edu.

00-1303 "Behavior of a Sandy Silt Reinforced with Discontinuous Recycled Fiber Inclusions"

Abstract: Standard laboratory compaction and consolidated undrained triaxial compression tests were performed on as-compacted and soaked specimens to assess variations in the compaction characteristics and load deformation response of a sandy silt reinforced with different percentages of randomly oriented recycled carpet fibers. Discrete, randomly distributed fiber inclusions significantly increased the peak shear strength, reduced the post peak strength loss, increased the axial strain to failure, and in some cases changed the stress strain behavior from strain-softening to strain-hardening for a sandy silt. Each of these changes in behavior is potentially beneficial for practical applications of this technique. Fiber inclusions impeded the compaction process, causing a reduction in the maximum dry density of reinforced specimens with increasing fiber content for a given compaction effort. If field specifications restrict the effort that can be applied during compaction, this can lead to decreased field performance however, many applications are not subject to such limitations. Accordingly, as the material being compacted changes from soil to soil with increasing amounts of fiber, compaction energy can also be increased to offset the effects that inclusions have on the compaction process. The strength losses associated with in service saturation were significantly reduced with fiber reinforcement. This study suggests that large volumes of recycled waste fibers can be used as a value-added product to enhance the shear strength and load deformation response of soils.

J.J. Murray, Parsons Brinckerhoff, Tel: 212-465-5273, Fax: 212-465-5592, J.D. Frost, Associate Professor, School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, Tel: 404-894-2280, Fax: 404-894-2281, Y. Wang, Associate Professor, School of Textile and Fiber Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, Tel: 404-894-7551, Fax: 404-894-9766.

00-1350 "Utilization of Construction and Demolition Debris Under Traffic-Type Loading in Base and Subbase Applications"

Abstract: As construction and remediation take place throughout New Jersey, the amount of construction and demolition debris increases, while the availability of landfill space decreases. A viable solution for the disposal of these materials is to incorporate them into base and subbase applications. An extensive laboratory program was conducted on two types of construction and demolition debris, recycled concrete aggregate (RCA) and recycled asphalt pavement (RAP). These two materials were compared with dense graded aggregate base coarse (DGABC), which is currently being used in base applications in New Jersey. Both the RCA and RAP were mixed at varying percentages with the DGABC to evaluate if an optimum mix blend could be formulated. The materials were evaluated under a traffic-type-loading scheme that included resilient modulus (M_R) and permanent deformation via cyclic triaxial testing. Laboratory tests concluded that the RAP, RCA, and DGABC blended materials all obtained higher resilient modulus values than the currently used DGABC. The permanent deformation results indicated that the RCA obtained the lowest amount of permanent deformation when the material was cyclically loaded to 100,000 cycles. In contrast, the permanent deformation testing on RAP resulted in the highest amount of permanent deformation at the same number of cycles. However, since both the RCA and RAP are materials with no current specifications in New Jersey, this study concluded that a blended mixture of 25 % RAP or RCA with 75 % DGABC would obtain approximately the same resilient modulus and permanent deformation properties as the DGABC currently used in New Jersey. This would enable the disposal of these materials within the base and subbase of the roadways without sacrificing the integrity of the roadway or vastly deviating from the specifications of the DGABC used in New Jersey. Existing models currently used for quarried base and subbase materials were also utilized to predict the permanent deformation in the recycled materials. Laboratory test results concluded these models could be used for predicting the permanent deformation in unbound recycled materials.

Thomas Bennert, Ali Maher, and Nenad Gucunski, Department of Civil and Environmental Engineering, Rutgers University, 623 Bowser Rd., Piscataway, NJ 08854-8014, Tel: 732-445-5376, Fax: 732-445 – 0577, Email: bennert@eden.rutgers.edu; and Walter J. Papp, Jr., Meuser Rutledge Consulting Engineers, 708 Third Ave., New York, NY 10017-4144, Tel: 212-490-7110, Fax: 212-490-6654.

00-1433 "Evaluation of Excess Foundry System Sands for Use as Subbase Material"

Abstract: Earthwork associated with highway construction provides an opportunity for high volume reuse of excess system sands (ESS) discarded by the foundry industry. California bearing ratio (CBR), unconfined compressive strength, and resilient modulus tests were conducted on 13 excess systems sands, one base sand, and two reference materials. Tests were conducted on specimens prepared dry of optimum, wet of optimum, and at optimum water content and using standard and modified Proctor compaction effort. Results of these tests were used to identify characteristic engineering properties of ESS, appropriate compaction conditions for ESS when used as subbase, and empirical equations that can be used to predict the engineering properties of ESS based on index properties. Results of the tests indicate ESS classify as SP, SM, or SP-SM (A-2-4 or A-3 in ASSHTO). The CBR of the ESS ranged between 4 and 40 and averaged 20 when compacted with standard effort at optimum water content. Using modified effort increased the CBR by as much as 850%. Swell during the soaking portion of the CBR tests was small for all ESS. ESS compacted at optimum water content with standard effort had unconfined compressive strengths ranging from 71 to 190 kPa. Resilient moduli of the ESS were similar to that of the reference subbase material, but smaller than the reference base material. A power function model in terms of bulk stress provided a good fit to the resilient moduli data from the ESS, the base sand, and the reference materials. Compaction dry of optimum or with greater compactive effort had minimal effect on the resilient modulus, but the resilient modulus decreased more than 50% when the ESS were compacted wet of optimum water content. A permanent deformation analysis was conducted with the resilient modulus data using the VESYS model. Results of this analysis showed that permanent strain in ESS should be small, and less than that of typical subbase as stresses expected in the field.

Jay R. Kleven, Tuncer B. Edil and Craig H. Benson, Department of Civil and Environmental Engineering, University of Wisconsin-Madison, 1415 Engineering Dr., Madison, WI 53706, Tel: 608-262-3225, Fax: 608-263-2453, Email: mailto:bahia@engr.wisc.edu.

00-0681 "Case Histories of Pavement Distress and Roadway Damage in Alaska Caused by Subsurface Moisture and Freezing Temperatures"

Abstract: Since 1992 Golder Associates has been working with the Municipality of Anchorage to evaluate the causes of pavement distress throughout the Municipality. During that period, design and construction changes have been recommended and implemented. The performance of pavements both before repair and after redesign has been monitored and evaluated. Surficial heave rates have been measured; ground temperature variations have been documented; crack patterns have been mapped; and soil profiles have been noted at various sites around the Municipality. In locations where drainage and insulation recommendations have been implemented, improved pavement performance has been observed. This paper presents case histories outlining the conditions initially observed in the distressed pavements and traces the performance of the pavements after being rebuilt according to our recommendations. Conclusion: Frost heave impacts pavements and other structures in cold regions. In the warmer cold regions, the impacts on pavements are frequently near-surface effects that result in cracking and the formation of depressions. In colder regions, deeper progressing frost fronts can result in surficial mounding that can result in longitudinal cracking in pavements. Water accumulated in the frost front during freezing can result in soil flows and slides on slopes during spring breakup. Thermal design considerations can minimize these impacts by reducing the contact of groundwater sources with an advancing heave front.

Rupert G. Tart, Jr., P.E., Principal, Golder Associates Inc., 1750 Abbott Road, Suite 200, Anchorage, AK 99507, Tel: 907-344-6001, Fax: 907-344-6011, Email: btart@golder.com.

00-0919 "Stone Interlayer Pavement Design"

Abstract: This project was initiated to evaluate the pavement performance of an alternative pavement design referred here as stone interlayer or inverted pavement. The test section consisted of a 4-inch (102 mm) layer of stone base on top of 6 inches (152 mm) of in-place cement stabilized base. The control section consisted of 8.5 inches (216 mm) of cement stabilized base layer on top of prepared subgrade (standard design). A 3.5-inch (99 mm) layer of flexible pavement was placed over both sections. The object of this experience was to evaluate reflective cracking reduction through the asphaltic pavement and overall pavement performance. The project was in Acadia Parish, Route LA 97 near Jennings, Louisiana. This is considered to be a low volume rural highway with an average daily traffic of 2,000 vehicles. The pavement was monitored for seven years after construction. During the evaluation period, annual crack survey, ride, and deflection measurements were collected. Additionally, as a part of the Louisiana Transportation Research Center (LTRC) accelerated pavement testing research program, the same pavement design was tested to failure using the Accelerated Loading Facility (ALF) device. The results of this investigation showed that the stone interlayer had significantly reduced the amount of reflective cracking. The ride characteristics and the structural capacity of both sections were all similar during the evaluation period. The accelerated testing results also verified the superior performance of stone interlayer pavement system. The cost analysis showed that the initial construction cost of stone interlayer system may be as high as 20 percent more than standard design. However, the life of stone interlayer pavement system is increased by almost five times the standard soil cement pavement as tested under accelerated loading. Conclusions: The test section with the stone interlayer pavement design experienced only 1/6 of the cracking of that of the control section with the soil cement pavement design after seven years of service. All the cracks in the test section were low severity, while some of the cracks in the control section were medium severity. The stone interlayer pavement design had almost five times the performance life compared to the soil cement pavement design under accelerated pavement testing. The initial investment increase of 20 percent for an inverted pavement is due to the cost of the crushed stone layer. However, for smaller traffic volume, an inverted pavement design with thinner asphalt will be more economical and provide longer service life than a soil cement pavement design. The stone interlayer test section had very similar structural capacity, ride characteristics, and rutting compared to the soil cement control section for the evaluation period.

Masood Rasoulian, Byron Becnel, Gary Keel, Louisiana Transportation Research Center, 4101 Gourrier Ave. Baton Rouge, La. 70808, Tel: 225-767-9112, Fax: 225-767-9108, Email: mrasouli@dotdmail.dotd.state.la.us.

00-0969 "Effectiveness Analysis of Subsurface Drainage Features based on

Design Adequacy"

Abstract: In order to prevent the deleterious effects of undrained moisture in pavement structures, it has become common to incorporate subsurface drainage features, such as permeable bases and edgedrains, into pavement design. A theoretical design methodology has been developed to ensure that the level of subsurface drainage provided is adequate for the specific pavement structure. Recent research (1) has called into question the effectiveness of subsurface drainage for certain types of pavement structures. By correlating the presence of moisture-related pavement distress with the presence of drainage features, it has been reported that drainage features do not significantly reduce faulting of doweled jointed concrete pavements, and that edgedrains may negatively impact hot-mix asphalt pavements. However, that study did not attempt to assess the adequacy of the provided drainage features using the theoretical design methodology. This paper presents an alternative method of effectiveness assessment based on design adequacy. The theoretical drainage capacity of a design feature, such as a pavement base or edgedrain system, is computed using the design methodology and compared with the expected inflow to that feature. The adequacy of the design is expressed as the proportion of the computed capacity to the expected service requirement. The method is applied to cases in the Long-Term Pavement Performance (LTPP) database. Examples are provided in which adherence to the design methodology would have indicated that the drainage features were inadequate; however, the more simplistic observational approach would reflect poorly on the effectiveness of the provided drainage features.

Timothy Robert Wyatt, Georgia Institute of Technology, 325185 Georgia Tech, Station, Atlanta GA 30332, Tel: 404-929-9185, Fax: 404-894-2281, Email: timothy.wyatt@ce.gatech.edu; Emir Jose Macari, Louisiana State University, Department of Civil and Environmental Engineering, Baton Rouge LA 70803, Tel: 225-388-8442, Fax: 225-388-8652, Email: emacari@lsu.edu.

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