Abstract:
The Oregon Department of Transportation (ODOT) has been placing 3/4-inch nominal maximum aggregate size (NMAS) open-graded wearing courses (OGWCs) in structural layers of 2 inches or more for about 30 years. Despite this, OGWC performance in the Pacific Northwest is not well understood. This study determined the use and performance of ODOT OGWCs, with special attention given to 3/4-inch open-graded HMA (previously referred to as "F-Mix") and recommends guidelines for the future use of OGWCs. The best estimated service life of ODOT 3/4-inch open-graded HMA ranges from 14 years (<5,000 ADT) down to 7 years (>100,000 ADT), which is less than comparable dense-graded mixes. The primary mode of distress is raveling and studded tire wear. Reduced service life, uncertain and unquantified safety benefits, and a possible greater risk of early failure lead to a recommendation to discontinue use of 3/4-inch open-graded HMA in Oregon as a standard surface mix. OGWCs used elsewhere in the U.S. are not likely suited for ODOT use because of their susceptibility to studded tire wear and are not recommended for adoption. If 3/4-inch open-graded HMA does continue in use, recommendations are as follows: (1) quantify its benefits, (2) restrict its use to low traffic (<30,000 ADT), (3) re-calibrate PMS expected life to be more in line with observed historical life, and (4) require the use of a windrow pick-up machine or end-dump transfer machine when paving OGWC.

Authors:
Muench, S.T., Weiland, C., Hatfield, J., Wallace, L.K.

Keywords:
Open-graded, hot mix asphalt, pavements, pavement performance

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Abstract:
This report identifies the key issues that must be considered by state and other highway operating agencies in selecting traffic equipment for collecting the truck volumes and load spectra needed for analysis and design of pavement structures. The report also identifies steps that must be taken to ensure that the equipment performs appropriately and that, as a consequence, the data collected accurately describe the vehicles being monitored. The report is a useful resource for state personnel and others involved in the planning and design of highway pavements and structures.

Authors:
Hallenbeck,M. E., Weinblatt,H.

Keywords:
analysis, data, design, highway, pavement, pavements, structures, traffic, truck, volume, Miscellaneous Library

Abstract:
This study documents the development of a pavement research framework for the Washington State Department of Transportation. The framework extends over a six-year period (three biennia) and includes provision for extensive collaboration with other agencies, the private sector, and national funding organizations.

Authors:
Mahoney,J. P., Pietz,M. D., Anderson,K. W., Pierce,L. M.

Keywords:
pavements, research, framework, prioritization

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Abstract:
The Washington State Pavement Management System (WSPMS) offers an organized methodology that WSDOT decision makers use to determine optimum strategies for providing and maintaining pavements in a serviceable condition over a given period of time. It also helps improve decision-making efficiency, provide feedback on the consequences of decisions, and ensure the consistency of decisions made at different management levels within WSDOT. Unfortunately, it is not possible, by simply scanning the WSPMS, to pinpoint reasons why pavement sections made of the same general surface materials and subjected to similar traffic and climatic conditions differ in performance. What the WSPMS can do is assist engineers in developing a candidate list of pavement sections with superior and inferior performance. Common characteristics that linkmultiple pavement sections are of particular interest, in part because they may reflect a common practice(e-g., nighttime construction) that leads to superior or inferior performance.This study undertook various extensive analyses and comparisons to help illustrate common attributes of Washington state pavements with superior and inferior performance. The research also reviewed field performance data for Interstate 90 within the 1999 version of the WSPMS. The purpose was to examine all pavement segments on the 480 km of Interstate 90 within Washington state.Reducing variability will allow WSDOT to produce more consistent pavement performance and will allow increasingly effective planning and forecasting. An almost certain byproduct of this increased planning effectiveness will be a more efficient allocation of available funding.

Authors:
Baker,M. J., Mahoney,J. P.

Keywords:
Assessment, condition, construction, data, effectiveness, forecasting, management, management system, materials, methodology, pavement, pavement management, pavement performance, pavement section, pavements, performance, planning, research, superior inferior, System, traffic, Washington, Washington state, WSDOT

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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 moldeling strategy and associated verification which permits analysis of multiple PCC plain jointed slabs. Several subbase/soil layers below the slabs and separation of the slab and base layer are considered. Load effects include those associated with both multiple tire and linear temperature gradients. A technique for modeling aggregate interlock shear transfer across PCC pavement joints is developed and verified. The overall development is contained in the computer program EverFE. The computer program uses a graphical user interface which aids its use.

Authors:
Davids,W. G., Turkiyyah,G. M., Mahoney,J. P.

Keywords:
aggregate, aggregate interlock, analysis, base, computer, computer program, developed, development, EverFE, finite element, Finite elements, ITS, Joints, joints load transfer, modeling, pavement, pavements, PCC, permits, program, rigid pavement, temperature, tire

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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:
An analysis was conducted of the impact that overweight vehicles have and will have on the life of the pavements in the Seattle metropolitan area. The study focuses on major Metro bus routes with both rigid and flexible pavements.Recommendations arc made to mitigate the impact of the higher loads from the bus fleet. These recommendations include route modifications to avoid streets with thinner, under designed pavements, increasing pavement thickness for rebuild or overlaid streets, and the purchase of vehicles, which meet legal axle loads.

Authors:
De Bolt,P. G., Chinn,E.

Keywords:
analysis, axle, bus, buses, heavy vehicles, impact, loads, overweight, pavement, pavement design, pavement service life, pavements, seattle, urban

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Abstract:
The major objectives of this study were to examine: (1) the types of recycled materials that are appropriate and feasible as alternative paving materials such as glass and tires; and (2) the types of recycled materials, such as mixed-plastics and compost, that can be utilized in all types of transportation applications other than pavements. Seven key products are investigated: tires; glass; asphalt concrete fly ash; compost; mixed plastics; and sign stock. Performance and cost data for pavements is documented for both in-state and nationwide applications. The national experience \'with the use of waste glass as an additive to asphalt concrete and its use in unbound base material is so highlighted. Programs for experimental use of recycled material are outlined. Recommendations for staffing and program changes to deal with recycling are also discussed.

Authors:
Swearigen,D. L., Jackson,N. C.

Keywords:
additive, Alternative, applications, asphalt, asphalt concrete, base, base materials, concrete, construction, cost, data, experimental, fly ash, Glasphalt, highway, highway construction, ITS, materials, objectives, pavement, pavements, performance, program, recycled ACP, recycling, Rubber-asphalt, tire, tires, transportation

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Abstract:
This paper presents the results of a research project to determine the long-term performance of wood fibre embankments, that were constructed by the Washington State Department of Transportation (WSDOT) beginning in 1972. At the time of their construction, concern existed that wood fibre fills would only provide a 15 to 20 year service life.Performance of existing wood fibre fills was evaluated based on thequality of the wood fibre material, quality of the effluent, and condition ofthe pavement. A visual classification system rating the wood fibre from freshto completely decomposed was developed and used in order to establish acriteria from which all wood fibre mater.ia1 could be -rated.. Visual examinationin conjunction with laboratory tests were used as determining aspects for theeffluent quality. The WSDOT Pavement Management System was used to evaluate relative pavement performance. Site descriptions are presented giving specificcharacteristics and properties of the fills inventoried, An analysis of t h i sinformation was done to determine the effectiveness of the fills.Over half the wood fibre samples were found to be nearly fresh or freshand none w e found to be completely decomposed. In all but one case, thepavement quality over the wood fibre fills surpassed the comparative highwaysegment rating indicating the wood fill\'s performance exceeded thatof the surrounding area. Generally, the surface water in the vicinity of thewood fibre was found to be clean and pure indicating no adverse impact ofeffluent. Given the above findings, embankments constructed of wood fibre werefound to perform well over ahnost a 20. year period. Service life in excess of50 years can be expected - of wood fibre fills.

Authors:
Kilian,A. P., Ferry,C. D.

Keywords:
analysis, condition, construction, developed, effectiveness, Embankments, evaluation, impact, Leachate, management, management system, pavement, pavement management, pavement performance, pavements, performance, performance evaluation, project, quality, research, tests, transportation, Washington, Washington state, Wood fibre, WSDOT

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Abstract:
The use of BoniFibers fiber reinforced Asphalt Concrete Pavement (ACP) at three City of Tacoma intersections is reported. Product selection, fiber reinforced ACP mix design, old pavement removal, construction and evaluations are documented.BoniFibers fabric reinforced ACP appears to provide a durable roadway at intersections that have a high volume of turning and heavy traffic. Continued monitoring of the City of Tacoma fiber reinforced ACP is recommended until major deterioration occurs.

Authors:
Toney,C. A.

Keywords:
asphalt, asphalt concrete, Asphalt Concrete pavement, Bonifibers, concrete, construction, design, deterioration, evaluation, fiber Reinforced ACP, fiber reinforced pavement, monitoring, pavement, pavements, Polyester Fibers, Polymar Fibers, roadway, traffic, volume

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Abstract:
The Washington State Department of Transportation (WSDOT) has completed construction of twenty-four hot-mix recycle projects as of January, 1985. At the begining of this study there were sixteen completed projects that were to be examined. Evaluation of the laboratory and pavement performance data shows that WSDOT\'s initial two projects, Renslow to Ryegrass (1977) and Yakima River to West Ellensburg Interchange (1978), are still performing very we1l. Although the other fourteed projects have been constructed only within the last two and a half years, the early data indicates equally promising results. Because of the impressive pavement performance exhibited by the recycled pavements, together with hot-mix recycle benefits such as conservation of natural resources, feasibility of construction, and its cost advantage over new ACP, hot-mix recycling has become an attractive addition to the WSDOT paving program.

Authors:
Peters,A. J., Gietz,R. H., Walter,J. P.

Keywords:
asphalt, asphalt concrete, benefit, benefits, construction, cost, data, evaluation, ITS, pavement, pavement performance, pavements, performance, program, project, recycling, rejuvenating agents, Study, transportation, Washington, Washington state, WSDOT

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Abstract:
The use of liquid anti-stripping additives (LAA) for reducing moisture damage in asphalt concrete pavements was evaluated using pavement cores from pairs of projects with-and-without LAA. Results were analyzed using the tensile strength ratio (TSR). In addition, a diazo-dye for determining the presence and concentration of LAA was attempted to access the value or the test as a field procedure. The chemical additive detection tests proved inclusive, but the TSR analysis gave a positive indication of the need for the use of LAA in the wetter environments of the state, For drier environments and for low traffic volumes, use of LAA may not be cost effective. The indirect tensile test was judged to be a potentially valuable tool for statewide use in the evaluation of stripping additive needs.

Authors:
Malsch,D. A.

Keywords:
additive, analysis, anti-stripping agents, asphalt, asphalt concrete, Asphalt Concrete pavement, bituminous concrete, Chemical, concrete, cost, cost effective, damage, detection, diazo-dye test, effectiveness, environment, evaluation, indirect tension test, moisture damage, pavement, pavement life, pavements, project, strength, stripping, tests, traffic, traffic volumes, volume

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Abstract:
This report summarizes the placement of sulfur extended asphalt (SEA) paving mixtures at two test sites near Pullman, Washington. One site was on an existing state highway and the other made use of the Washington State University Test Track. The report includes the preliminary mix designs, pavement thickness determination, construction details and initial performance data for the test pavements. A major experimental feature of the study was the use of 0/100 (conventional asphalt concrete), 30/70 and 40/60 SEA binder ratios in the experimental paving mixtures.

Authors:
Mahoney,J. P., Christensen,D. R., Terrel,R.

Keywords:
asphalt, asphalt concrete, asphalt pavement, concrete, construction, data, design, evaluation, experimental, extended asphalt, highway, mixture, pavement, pavement evaluation, pavement performance, pavements, performance, Study, sulfur, test track, Washington, Washington state

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Abstract:
Tests were conducted on various pavements t o investigate the correlation between measurements obtained using the Impulse Index Computer and pavement condition as determined by other means. Benkelman Beam deflection measurements and Impulse Index measurements are compared along with Washington State Pavement Rating System results. Effect of temperature on the apparent Impulse Index is evaluated..

Authors:
Brands,F., Cook,C. J.

Keywords:
Benkleman beam, computer, condition, Deflection test, impulse index, impulse testing, index, pavement, pavement condition, pavement deflection, pavement evaluation, pavement maintenance, pavements, systems, temperature, tests, Washington, Washington state

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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:
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 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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Abstract:
The purpose of this study was threefold: (1) Develop empirical equivalencies from all four rings, (2) develop a design method for overlays based on field deflections; and (3) evaluate the validity of data obtained from instrumentations in terms of n-layer elastic theory and then develop theoretical equivalencies.This was done. Field equivalencies were developed and they indicated that superiority of the treated base materials over the untreated. A design method was developed which could be used for predicting when an overlay was needed and what thickness was needed to withstand certain equivalent wheel loads and deflections.Using computer programs for n-layer elastic theory developed by Chevron Research Company, deflection stresses and strains were computed and compared with field data. Assumptions about the material behavior and condition were made based on laboratory data obtained from The Asphalt Institute and field knowledge, and were used to help predict the behavior of pavements. The results were encouraging and indicate that field measurements generally were comparable with elastic layer theory predictions. This will help to develop and modify existing design limits for stresses, strains and deflection for future work.Equivalencies based on theoretical deflections, stresses and strains indicate the difficulty of assigning precise values. These values also indicate the superiority of treated materials over the untreated materials.

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

Keywords:
analysis, asphalt, base, base materials, behavior, computer, computer program, condition, data, design, equivalencies, evaluation, experimental, loads, materials, overlay, overlays, pavement, pavements, prediction, program, research, strains, stresses, volume, wheel load

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