Abstract:
This study identifies and evaluates hot mix asphalt (HMA) mix design and construction techniques with potential for improving WSDOT pavement surface life. WSDOT pavement failure mechanisms are found to be predominantly cracking. Rutting may reach a failure threshold first in areas with high traffic or studded tire use. A literature review, survey of state DOT practices, case study, WSPMS (Washington State Pavement Management System) data analysis, and limited laboratory testing identified 17 construction and mix design techniques with promise. Of these 17 techniques the use of stone matrix asphalt (SMA) mixtures for high-traffic interstate routes, 3/8-inch nominal maximum aggregate size mixes for medium/low traffic routes and mountain passes, non-Superpave aggregate gradation, reduced N-design gyration levels for Superpave mix design, and warm mix asphalt (WMA) to aid compaction are highly recommended for further investigation and implementation. Other techniques recommended for further investigation and possible implementation are: adoption of a cracking performance test for Superpave mix design; applying a BST within a year of paving to reduce pavement surface aging; specifying the use of Pave IR for mountain pass jobs and cold weather paving; and using steel slag aggregate in situations that call for improved friction and resistance to studded tire wear (i.e., at mountain passes).

Authors:
Wen, H., Muench, S., Chaney, S., Littleton, K., Rydholm, T.

Keywords:
Asphalt pavement, Cracking, Rutting, Climate, Studded tire wear

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Abstract:
The detrimental effects of low compaction temperatures or aggregate segregation have been documented for at least forty years. Lower compaction temperatures are directly related to an increase in air void content, which decreases the strength of the pavement. Even with a perfect mix design, if the mix is not properly compacted in the field, the final product will not last for its intended length of time.The goals of this study were to determine what kind of problem the Washington State Department of Transportation (WSDOT) experiences with hot-mix paving, whether temperature differentials or aggregate segregation or both, the possible causes of those problems, and what WSDOT can do to fix the problem. The study found that WSDOT experiences temperature differentials on many projects and to some extent aggregate segregation (typically in longitudinal streaks). The study also found that because many factors are involved with paving operations, no one single piece of equipment or operation will guarantee that temperature differentials willnot occur, but that techniques can be utilized to offset the effects of the temperature differentials.The study utilized a density profile procedure that provides a method of determining the effect of the temperature differentials in the finished product. It can locate potential areas of low density, test those areas, and provide results (via a nuclear asphalt content gauge) to determine the extent of the problem.Density differentials are a primary concern in hot-mix paving. If temperature differentials exist, but the finished pavement has a uniform density of 93 percent or greater for dense-graded mixes, then the pavement should serve its intended purpose for its intended length of time. The density profile procedure does not guarantee a uniform mat density, but it can be used as a quality control tool to help attain a uniform density. This could be a major step in achieving a higher quality hot-mix product.

Authors:
Willoughby, K.A., Read, S.A., Mahoney, J.P., Muench, S.T., Pierce, L.M., Thompson, T.R., Uhlmeyer, J.S., Moore, R., Anderson, K.W.

Keywords:
Hot-mix pavement, asphalt pavement, temperature differentials, density differentials, density profile, inplace density

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External Links: http://www.wsdot.wa.gov/research/reports/fullreports/476.1.pdf http://wsdot.wa.gov/Research/Reports/400/476.1.htm

Abstract:
Funded by the 1987 Intermodal Surface Transportation Efficiency Act, the Strategic Highway Research Program (SHRP), was a five year, $150 million research program to improve the performance of the nation\'s roads by addressing four key areas: concrete and structures; highway safety and maintenance; asphalt; and long-term pavement performance. Nearly one-third of the $150 million was allocated for the study of asphalt, specifically to develop performance based specifications that would relate material properties of the binder and the mix to field performance. Superpave (Superior PERforming asphalt PAVEments) encompasses the products of the SHRP asphalt research program and consists of three interrelated elements: an asphalt binder specification with supporting tests; a mix design and analysis system with supporting tests; and performance prediction models. This report is a compilation and synthesis of Washington DOT\'s (WSDOT) experience with selected components and concepts of the SHRP/Superpave technology to include the following: performance graded (PG) binder usage and specification validation; gyratory mix design; the Superpave Shear Test (SST); and field performance of the Superpave mixes.Binders typically specified by WSDOT (AR400OW and PBAs -2, -5, -6. -6GR) were classified in terms of five Superpave performance grades: PG 58-22; 64-22; 64-28; 64-34; and 70-28. Although data from 171 weather stations suggest that as many as 6 low- and 5 high-temperature grades could be specified, binder availability and regional pavement distress were used to develop guidelines for statewide PG usage. Three binders were recommended for use in the western, northeastern and southeastern regions of the state as follows: PG 58-22; PG 58-34; and PG 64-28, respectively. Validation of the binder specification with respect to low temperature cracking was accomplished using binder and field performance data from 28 projects. The results were very encouraging: the original SHRP algorithm for binder selection correctly \"predicted\" field performance in 22 of 28 cases, whereas the LTPP algorithm for binder selection correctly \"predicted\" field performance in 26 of 28 cases.Additionally, a laboratory experiment using the Superpave Shear Test (SST) apparatus was undertaken to test the effectiveness of binder \"bumping,\" i.e., increasing the high temperature grade because of exceptionally high traffic volume and/or slow or standing traffic. The data clearly indicate that the SST is an effective tool for discriminating between binders and that \'bumping\" may be effective in reducing pavement rutting. Permanent shear strain for specimens made with a PB 70-xx binder was only 25 to 33% of the shear strain for specimens made with a PG 58-xx binder.As originally configured, the Superpave mix design matrix included seven traffic levels and four temperature regimes for 28 possible compaction levels. Recognizing that the 28 compaction levels made for a somewhat unwieldy system, WSDOT attempted to reduce the number of compaction levels by conducting a series of mix designs at each compaction level. The results of the limited experiment suggest that it might be possible to limit the number of compaction levels required for mix design. Research by Brown et. al. (NCHRP 99) tends to confirm this as they have suggested reducing the number of compaction levels and provided more definitive guidance with respect to each level.Since 1993 WSDOT has place 44 projects which include some component of the Superp ave technology. For 17 of these projects parallel Hveem and Superpave mix designs were conducted. In 13 of the 17 cases, the Superpave design asphalt content was equal to or greater than the Hveem design asphalt content, though the difference was usually no more than 0.2%. A fundamental difference between Hveem and Superpave mix design methods is the compaction device. Data from these field projects indicate that the current kneading and gyratory compaction protocols (at least for 109 gyrations) yield similar air void contents.As noted previously, Washington DOT has placed 44 projects which involve some component of the Superpave technology. For 18 of the projects a conventional Hveem mix design was conducted using a PG binder (Hveem-PG). The remaining 26 projects were truly Superpave, i.e., the materials selection and mix design were established in accordance with the Asphalt Institute\'s SP2, Superpave Level 1 Mix Design. According to WSDOT practice the following numerical indices trigger maintenance: Pavement Structural Condition (PSC) 10 mm; or International Roughness Index (IRI) > 500 cnVkm. Although relatively \"young\", the 44 projects are performing quite well. The average values of rutting, PSC, and IRI (4, 91, and 121, respectively) are all well below the \"trigger\" values. With respect to rutting and PSC, the performance of Hveem-PG and Superpave projects is virtually identical. However, the ride quality of the Superpave projects is a bit rougher than the Hveem-PG binder projects: IRI of 134 for the former and 103 for the latter. The higher values of IRI measured on the Superpave projects may be the result of the typically coarser aggregate gradation or differences in construction techniques.WSDOT\'s Superpave experience has not been without challenges. Still, its overall experience has been very encouraging. Experimentation with the revised compaction matrix, continued use of the SST, field validation of the \"bumping\" experiment, and long-term monitoring of field performance will provide the necessary data to allow WSDOTs critical assessment of Superpave\'s technical merit and economic viability.

Authors:
Leahy,R. B., Briggs,R. N.

Keywords:
SHRP, Superpave, asphalt, intermodal, transportation, transportation efficiency, highway, research, program, performance, concrete, structures, highway safety, safety, maintenance, pavement, specifications, specification, asphalt pavement, pavements, tests, design, analysis, prediction, models, Washington, WSDOT, data, temperature, cracking, LTPP, traffic, volume, compaction, materials, condition, international roughness index, roughness, index, ride quality, quality, aggregate, construction, ITS, monitoring

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Abstract:
This report documents the construction of two experimental test sections of asphalt concrete pavement containing polymer and ground rubber additives. The two sections are located on I-5 south of Olympia, Washington and were constructed in the summer of 1992.The test sections were paved with an open-graded using PBA-6 and asphalt cement binders. PBA-6 is a performance based asphalt cement with a polymer additive. is a performance based asphalt cement but with ground tires as the additive. The is a for a new product developed by the U.S. Oil and Refining Company of Tacoma, Washington. The completed test sections are performing well, although the PBA-6GR section is flushing due to too high of an initial asphalt content. The sections will be monitored of 10 years to determine long-term performance.

Authors:
Livingston, J., Anderson, K.W.

Keywords:
Additive, asphalt, asphalt concrete, Asphalt Concrete pavement, Asphalt content, asphalt pavement, concrete, construction, counties, crumb-rubber, developed, experimental, line, open-graded, pavement, pavements, performance, performance based specifications, polymer, rubber, tire, tires, Washington

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Abstract:
The performance of an experimental installation of PlusRide ACP as a bridge deck overlay is summarized in this report. Visual inspections, friction tests, noise readings, and rut depth measurements were taken on both the PlusRide and a rubberized ACP control section. No evidence of better frictional properties, noise reduction or increased service life could be attributed to the PlusRide in comparison with the rubberized ACP control section.

Authors:
Allison, R.E.

Keywords:
Asphalt, asphalt pavement, bridge, bridge deck, bridge deck overlay, control, Deck, experimental, friction, inspection, noise, noise reduction, overlay, pavement, performance, PlusRide, resistance, Rubberized, tests

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External Links: http://wsdot.wa.gov/Research/Reports/100/130.2.htm

Abstract:
This is the final report of PlusRide being used as the wearing course on a bridge deck overlay.A Class D Asphalt Concrete pavement which is an open graded friction course was used on an adjacent bridge as a control for the PlusRide. The PlusRide claims were high friction resistance, reduced noise, increased fatigue properties and deicing characteristics. The PlusRide cost 50 percent more that the Class D and the friction resistance, noise levels and fatigue properties were the same for the PlusRide and Class D. The deicing characteristics could not be confirmed due to the absence of surface icing on highways in the Yakima area.

Authors:
Peters, A.J., Schultz, R.L.

Keywords:
Asphalt, asphalt concrete, Asphalt Concrete pavement, asphalt pavement, bridge, bridge deck, bridge deck overlay, claims, Class D, concrete, control, cost, Deck, fatigue, friction, highway, Highways, noise, overlay, pavement, PlusRide, resistance

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Abstract:
This is the post construction and one year evaluation Report of being used as the wearing course on a bridge deck overlay under very high traffic volumes. A rubberized Class D Asphalt Concrete Pavement friction course was used on an adjacent bridge to compare against the PlusRide. The properties evaluated were friction resistance, noise, fatigue properties and deicing characteristics. The friction and noise properties are the same. The PlusRide has deeper ruts and large areas in the traveled lane have delaminated. The deicing characteristics have not been confirmed. The rubberized class ACP is performing better than the PlusRide.

Authors:
Peters, A.J., Schultz, R.L.

Keywords:
Asphalt, asphalt concrete, Asphalt Concrete pavement, asphalt pavement, bridge, bridge deck, bridge deck overlay, bridges, Class D, concrete, construction, Deck, evaluation, fatigue, friction, friction course, noise, overlay, pavement, PlusRide, resistance, Rubberized, traffic, traffic volumes, volume

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Abstract:
This report describes the construction of experimental asphalt-rubber open-qraded friction course overlays on I-5 in Vancouver, Washington. A 1200 foot section of open-graded pavement was included as a control section. Evaluations will be conducted over a period of three years to measure the performance of the rubber and polymer sections against the control section of conventional open-graded pavement.Initial observations and tests show no significant differences between the control and the asphalt-rubber and polymer sections.

Authors:
Anderson, K.W.

Keywords:
Asphalt, asphalt pavement, Asphalt-Rubber, construction, control, evaluation, experimental, friction, friction course, open-graded, overlay, overlays, pavement, performance, PlusRide, polymer, rubber, tests, Washington

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Abstract:
Statewide sampling of highway runoff continued through 1980-81, and the resulting data has been aggregated with that from previous years to further investigate pollutant loadings. Results have validated the solids loading model previously proposed by Asplund (1980) for Western Washington Highways and tentatively extended the model to Eastern Washington. Loading of there pollutants can be predicted from total suspended solids loading using ratios derived from the data. These ratios may be taken as constants at any Washington State location for some pollutants or as linear functions of traffic or other contaminants. Comparison of runoff from a sulfur-extended asphalt pavement with runoff elsewhere indicates higher sulfate loads in the former case. A limited sampling program along an uncurbed highway section observed higher pollutant concentrations from these sections to curbed areas. Sampling of solids adhering to the undercarriage of automobiles produced widely varying results but suggested that vehicles traveling on rural or unpaved roads accumulate significant amounts of solids that can be released on highways. The final year of field sampling will concentrate on improving the loading models, especially for Eastern Washington application, and continuing the sulfur extended asphalt study with a functional control site experiencing the same conditions.

Authors:
Tai Wik, D.C., Mar, B.W., Horner, R.R.

Keywords:
Analysis, asphalt, asphalt pavement, concentrations, condition, control, data, extended asphalt, highway, highway runoff, Highways, loads, model, models, pavement, pollutant loading, Pollutants, program, runoff, rural, sampling, statistical analysis, sulfur, suspended solids, traffic, Washington, Washington state

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Abstract:
Two forms of pavement distress were noted on recent asphalt concrete overlay projects. A general loss of wearing surface under traffic action, termed surface ravelling, was observed on three projects starting the first season after construction.Two forms of pavement distress were noted on recent asphalt concrete overlay projects. A general loss of wearing surface under traffic action, termed surface ravelling, was observed on three projects starting the first season after construction. A concentrated, local loss of surface material in narrow longitudinal strips, designated as strip ravel ing, was observed on four projects approximately the second season after completion. Construction record reviews and field testing and sampling of these projects along with four undistressed projects were made to define the construction methods and equipment used and to obtain samples from areas of good and bad pavement condition. These samples were tested to determine the strength of the compacted mix, and of the aggregate and asphalt constituents. Common factors from the projects showing surface ravelling were a thin lift pavement overlay placed late in the paving season with a tendency toward less than optimum asphalt content. The resulting pavement had high air void content and was readily abraded by traffic during ensuing severe winter weather. Recurrence of this type of problem can best be prevented by increased emphasis on proper compaction and mix design. Remedial work on the present projects should be directed toward a seal coat application. Strip ravelled projects were found to have similar pavement properties in ravel and non-ravel led sections and general to be within desirable limits. Lower strength in resilient modulus tests and physically observed asphalt stripping in the ravelled sections indicate a localized failure of the asphalt aggregate bond. The failure occurrence in narrow longitudinal strips indicates a cause associated with paving operations--possibly differential compaction or hydrocarbon contamination. Preventive measures should ensure uniform compaction and more thorough checking of stripping tendencies. Corrective measures will require continued patching and possibly removal and replacement of affected pavement.

Authors:
Gietz, R.H.

Keywords:
Aggregate, asphalt, asphalt concrete, asphalt pavement, compaction, concrete, condition, construction, construction methods, contamination, design, Distress, investigaton, overlay, pavement, resilient modulus, sampling, season, strength, tests, traffic, winter

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Abstract:
There are indications that many trucks now have front axle loads approaching the maximum allowable for single axles which increases the potential for pavement damage. This report is intended to be a State-Of-The-Art approach to answer several pertinent questions from a theoretical study based on hypothetical pavements and loads, but based on reasonable material characteristics and pavement behavior from previous research. The results are a series of relationships based on pavement life which can be used to determine any number of \"equivalencies.\" These equivalencies can be used to compare the destructive effects of various sizes of single and dual tires, axle loads , pavement thicknesses , speed and temperatures. The general nature of this report provides a wide range of conditions for comparison.on a relative basis.

Authors:
Terrel, R., Rimsritong, S.

Keywords:
Asphalt pavement, axle, behavior, condition, damage, dual tires, equivalencies, loads, pavement, pavement damage, pavement life, pavements, research, single axle, speed, speed and temperature, state-of-the-art, temperature, tire, tire contact pressure, tires, truck, trucks, wheel load

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Abstract:
This report presents results obtained from the analyses of data which were collected during the performance of Phase I and Phase of this project. The data were at the A. Riedesel Pavement Testing Facility which is operated by Washington State University and is located in Pullman, Washington. Regression analyses were formed in order to relate various factors to each other. The factors used in the analyses included stud type, stud protrusion, speed, air temperature, pavement temperature, environmental conditions, stud hardness and tread depth. The purpose was to evaluate the relative importance of these factors pavement wear. It was found that the type of overlay, the type of stud and the protrusion length were the most important factors affecting pavement wear under Test conditions. The other factors could not be sufficiently isolated to determine their relative importance. Average wear rates were calculated for the different types of pavements and by the different stud types. A formula was developed which can be used to calculate pavement life under certain conditions. The results obtained for Phase I and Phase were compared and the difference in these results is discussed. Some of the difference was due to the different between the two phases A comparison with other associated research was madeA striping paint study was made and the results are in this report.

Authors:
Sorensen, H.

Keywords:
Condition, data, developed, environmental, facilities, overlay, pavement, Pavement Durability, life & performance, asphalt pavement, portland cement concretes, overlays, surface textures, studded tires, skid resistance, pavement life, pavement temperature, pavements, performance, project, regression, repair, research, speed, striping, striping paints, Studded, studded tire, Study, temperature, tire, Washington, Washington state

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Abstract:
In many parts of the world, the design of flexible pavement is still based on empirical methods which have developed from engineering experience. These empirical methods cannot be extrapolated beyond their limits without full scale trials to prove their applicability. In recent years, however, the increase of traffic, both in volume and axle loads, has led to the failure of many roads previously considered well designed. For this reason, therefore, researchers realized that a closer look at the pavement materials was desirable in order to develop a rational design procedure. Due to the complexity of characterizing pavement materials, and the limitations of instrumentation, much of the reported work offered little help in changing design practice. This is, perhaps, due to many simplifying assumptions which had to be introduced in the experimental procedure as well as the interpretation of the test results. Recently, however, there has been a sharp advancement in test instrumentation and an outstanding progress in processing the experimental results. This has been reflected through many fine investigations and has increased the demand for more improvements. An asphalt pavement is a complex structure whose function is to provide a suitable surface for a highway, an airport, or other off-highway facility. The load of a vehicle or an aircraft is transmitted through the multilayered system of processed materials which have different mechanical properties. The stress distribution within this system is highly complex and to a large extent is dependent on the relative stiffnesses of the individual layers.

Authors:
Terrel, R.L., Awad, S.

Keywords:
Asphalt, asphalt pavement, axle, base, behavior, demand, design, developed, experimental, facilities, fine, highway, improvement, loads, materials, methods, pavement, stiffness, stresses, System, traffic, volume

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Abstract:
This report presents results obtained from testing at the G. A. Riedesel Pavement Testing Facility at Washington State University during the period from February 11 to May 4, 1972. The purpose of this project was fourfold: 1) to determine pavement wear caused by studded tires ; 2) to evaluate the resistance of different pavement materials and textures used in the states of Washington and Idaho to wear caused by tire studs; 3) to test pavement materials and overlays to reduce tire stud damage; and, 4) to study the effect of studded truck tires on pavements. Ring #5 consisted of three concentric tracks on which 16 tires travelled in eight wheel paths. Three studded types and unstudded passenger tires , three studded and unstudded truck tires, and 46 sections of various types of pavement materials surface overlays and surface textures were tested. The results are based on wear in terms of rate of wear, area removed, maximum and average rut depth using the WSU Profilometer, and the camera wire shadow apparatus, and are valid only under WSU testing conditions. The findings indicate that some pavement materials are more resistant to the effect of studded tires than others. All types of studded tires tested caused some pavement wear and this affected the skid resistance values. The new types of studs reduced wear of various pavement materials. Studded truck tire wear was less than expected due to equipment problems.

Authors:
Krukar, M., Cook, J.C.

Keywords:
Camera, condition, damage, equipment, facilities, materials, overlay, overlays, pavement, Pavement Durability, life & performance, asphalt pavement, portland cement concretes, overlays, surface textures, studded tires, skid resistance, pavements, project, repair, resistance, skid resistance, studded tire, studded tires, studs, Study, tire, tires, truck, Washington, Washington state

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Abstract:
This preliminary report presents data obtained from testing at the L A Riedesel Pavement Testing Facility during the period from February 11 t o May 4, 1972. The purpose of this project was four fold: (1) to determine pavement wear caused by studded tires; (2) to evaluate the resistance of different pavement materials and textures used in the states o f Washington and Idaho to wear caused by tire studs; (3) t o test pavement materials and overlays to reduce tire stud damage; and, (4) to study the effect of studded truck tires on pavements.This preliminary report presents data obtained from testing at the G. A. Riedesel Pavement Testing Facility, during the period from February 11 to May 4, 1972.

Authors:
Krukar, M., Cook, J.C.

Keywords:
Damage, data, facilities, materials, overlay, overlays, pavement, Pavement Durability, life & performance, asphalt pavement, portland cement concretes, overlays, surface textures, studded tires, skid resistance, project, resistance, studded tire, studded tires, studs, Study, tire, tires, truck, Washington

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Abstract:
This report presents results obtained from testing at the A. Riedesel Pavement Testing Facility at Washington State University during the period of November 20, 1972 to May 1973. The purpose of this project was three-fold: (1 to determine pavement wear caused by studded tires; 2) to evaluate the resistance of different pavement overlays used in the states of Washington and Idaho to wear caused by studs; and 3) to test pavement materials and overlays to reduce tire stud damage. Ring and Phase of this project consisted of three concentric tracks on which 16 tires traveled in eight wheel paths. Four types of studs in passenger snow two types of passenger tires, and unstudded truck tires, and 22 sections of various types of pavement overlays and surfacings were tested. Four different stripes were also tested. The results are based on wear in terms of rate of wear, area removed, maximum and average rut depths using the WSU profilometer and the camera wire shadow box apparatus. Skid resistance values were measured using the California Skid Tester and the English Portable Skid Tester. The results are valid only under WSU testing conditions. The findings indicate that some pavement overlays are resistant to the effect of studded tires than others. All types of studded tires tested caused some pavement wear and this affected skid resistance values. Some of the newer types of studs reduced wear of various pavement overlays. The pavements having the most wear resistance had the skid resistance retention characteristics. Additives to asphalt skid resistance helped wear resistance characteristics but lowered skid resistance on characteristics.

Authors:
Krukar, M., Cook, J. C.

Keywords:
Asphalt, California, camera, condition, damage, facilities, materials, overlay, overlays, pavement, Pavement Durability, life & performance, asphalt pavement, portland cement concretes, overlays, surface textures, studded tires, skid resistance, pavements, project, repair, resistance, skid resistance, snow, studded tire, studded tires, studs, tire, tires, truck, Washington, Washington state

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