Abstract:
The durability performance of asphalt concrete (AC) with various percentages of reclaimed asphalt material (RAM) has been a focal point of the asphalt industry, leading it to embrace the balanced mix design (BMD) concept. The goal of this research was to review and enhance WSDOT\'s AC materials selection, mix design, and standard specifications for optimized use of RAM, based on readily implementable technology, in collaboration with industry stakeholders for improved durability performance. The scope included a literature review, an assessment of RAM supply in the state, and a statewide comparison of low and high RAM pavement performance data to determine whether differences were observed;. The scope also included an evaluation of raw materials and field mixtures and an evaluation of laboratory mixed-laboratory compacted (LMLC), field mixed-laboratory compacted (FMLC), and field cored (FMFC) samples. The laboratory analysis included short-term and long-term aging of binders and mixtures with rheological and cracking tests performed on them. One recommendation of the study was to integrate volumetric parameters along with further performance testing in a BMD approach to increase effective binder content. Another was to implement all of the volumetric criteria in AASHTO M323 during mix design, test section and acceptance. Additional recommendations were to use ΔTc as an aging parameter in binder specifications; include RAM in all mix designs regardless of doses; maintain an IDT strength specification and transition to the CT-Index; add long-term aging for IDT/CT-Index test specimens in the future, maintaining the current Hamburg Wheel Track (HWT) rutting test and criteria; revise short- and long-term standard specification; and re-evaluate the performance of RAM pavements with time.

Authors:
Muench, T., Hand, A., Sebaaly, P., Hajj, E., Chhetri, K., Piratheepan, M., Elias, N., Howell, R., DeVol, J., Davis, S,

Keywords:
Asphalt concrete, performance, recycled asphalt materials, durability

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Abstract:
This study investigated the influence of several factors on the adhesive bond provided by the tack coat at the interface between pavement layers. These factors included the surface treatment, curing time, residual application rate, and coring location. Three tests were performed for measuring the bond strength between an existing hot mix asphalt (HMA) and a new HMA overlay, namely the Florida DOT Shear Tester, the UTEP Pull Off Test, and the Torque Bond Test. Testing involved a CSS-1 type emulsion as the tack coat. The results from the three tests were statistically analyzed. Generally, milling provided a significantly better bond at the interface between the existing surface and the new overlay. Curing time had a minimal effect on the bond stength. The results indicated that the absence of tack coat did not significantly affect the bond strength at the interface for the milled sections, whereas it severely decreased the strength for the non-milled sections. The results also showed that increasing the residual rate of tack coat did not significantly change the bond strength at the interface. Lastly, the coring location was found to be an insignificant factor.

Authors:
Tashman,L., Nam,K., Papagiannakis,T.

Keywords:
Tack coat, interface, bond strength, shear strength, test for tack coat, statistical analysis, performance

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Abstract:
This report documents the development of data collection methodologies that can be used to cost effectively measure truck movements along specific roadway corridors selected by transportation agencies in Washington State. The intent of this study was to design and test methodologies that could be used to measure the performance of freight mobility roadway improvement projects against benchmarks, or selected standards, that would be used both as part of the project selection process and to report on speed and volume improvements that resulted from completed freight mobility projects. One technology tested was Commercial Vehicle Information System and Networks (CVISN) electronic truck transponders, which are mounted on the windshields of approximately 20,000 trucks in Washington. By using software to link the transponder reads from sites anywhere in the state, the transponder-equipped trucks could become a travel-time probe fleet. The second technology tested involved global positioning systems (GPS) placed in volunteer trucks to collect specific truck movement data at 5-second intervals. With GPS data it was possible to understand when and where the monitored trucks experienced congestion and to generate useful performance statistics. The study found that both data collection technologies could be useful; however, the key to both technologies is whether enough instrumented vehicles pass over the roadways for which data are required. This basic condition affects whether the technologies will be effective at collecting the data required for any given benchmark project. The report also recommends the traffic data that should be collected for a benchmark program and the potential costs of using either data collection technology.

Authors:
McCormack,E. D., Hallenbeck,M. E.

Keywords:
agencies, commercial vehicle, condition, congestion, construction, corridors, cost, costs, data, data collection, design, development, freight, freight mobility, freight movement reliability, global positioning, global positioning systems, GPS, improvement, methodology, mobility, networks, performance, positioning, probe program, project, research, roadway, software, speed, statistics, Study, System, systems, technology, traffic, traffic data, transportation, travel time, truck, truck monitoring, trucks, volume, Washington, Washington state

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External Links: http://www.wsdot.wa.gov/research/reports/fullreports/607.1.pdf http://wsdot.wa.gov/Research/Reports/600/607.1.htm

Abstract:
In 2003, the Washington State Department of Transportation (WSDOT) initiated a research effort to develop and test a methodology for estimating congestion delay on Seattle area freeways. The initial phase of the research developed a preliminary methodology for both measuring congestion and assigning that congestion to specific lane blocking incidents. In Phase 2 of this study, that methodology was automated and extended to include an examination of the effects of incidents occurring on the shoulders of the freeway, spillback from incident-caused congestion on one freeway that affects a second freeway that feeds traffic onto the initially congested facility, special events, and weather. Because funding for this effort was extremely limited, only three corridors (with both directions analyzed independently) and two months of data were analyzed. The project found that the Phase 1 methodology works well in assigning traffic congestion that occurs in the immediate time frame and geographic location of incidents to those incidents. It also showed that this process can be automated, making the data preparation effort now the primary determinant of the cost of additional work of this kind. Unfortunately, even with the addition of shoulder incidents, special events, and weather to lane blocking events, the automated process is unable to assign a significant proportion of the non-recurring delay occurring on Seattle freeways. The detailed analysis of freeway performance showed that much of the delay caused by specific incidents occurs in places or at times removed from the incident itself. The result is that much of the observed non-recurring delay can not be assigned to specific causes by the current analytical process. New analytical procedures will need to be developed in Phase 3 of this work. The Phase 2 analysis also confirmed that the congestion effects of specific incidents and other traffic disruptions are highly dependent on the background traffic conditions at the time of the disruption. While the Phase 2 analysis did not produce all of the results desired, the additional analyses showed that the summary statistics output from the Phase 2 software are useful as input to other analytical procedures.

Authors:
Kopf,J., Nee,J., Ishimaru,J. M., Hallenbeck,M. E.

Keywords:
congestion causes, freeway performance, traffic congestion, Washington, Washington state, transportation, WSDOT, research, methodology, congestion, seattle, freeway, developed, incident, Study, effects, traffic, facilities, corridors, data, project, cost, analysis, performance, in-place, condition, statistics, software

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External Links: http://www.wsdot.wa.gov/research/reports/fullreports/619.1.pdf http://wsdot.wa.gov/Research/Reports/600/619.1.htm

Abstract:
This research addresses the understanding of, and need for, load spectra in future pavement design procedures and as a stepping stone toward more complete pavement design. The primary objective of this project was to develop truck axle load spectra for Washington State. To do this, axle load data collected at WIM stations throughout Washington State were used. The developed load spectra encompass the principal truck axles on the roadway network: single, tandem, and tridem. Achieving this objective allows the Washington State Department of Transportation, or any state highway agency with analogous traffic patterns, to accommodate the requirements of the 2002 Design Guide, developed through NCHRP Project 1-37A. A secondary objective of this project was to determine whether ESALs obtained from the developed load spectra are significantly different from historical values. Because the developed load spectra are transformable to ESALs, state highway agencies that decide not to use the new guide can still choose to employ the ESALs produced with the load spectra. The project concluded that the developed load spectra are reasonable. For single axles they are comparable to the 2002 Design Guide and MnROAD defaults. For tandem and tridem axles, they are slightly more conservative than defaults of the 2002 Design Guide and MnROAD, but they are still within reason. In addition, the ESALs per vehicle class associated with the developed load spectra are comparable to Washington State historical ESALs for vehicle classes 9, 10, and 13. The use of the newly developed ESALs per vehicle will generally increase design ESALs, but that increase will be due to inclusion of the less predominant vehicle classes (4, 6, 7, 8, and 11).

Authors:
Al-Yagout,M. A., Mahoney,J. P., Pierce,L., Hallenbeck,M. E.

Keywords:
agencies, axle, data, design, developed, development, equivalent single axel load, ESAL, highway, load spectra, pavement, pavement design, performance, project, research, roadway, single axle, traffic, transportation, truck, Washington, Washington state, weigh-in-motion, WIM

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External Links: http://www.wsdot.wa.gov/research/reports/fullreports/600.1.pdf http://wsdot.wa.gov/Research/Reports/600/600.1.htm

Abstract:
The Falling weight deflectometer test (FWD) is a commonly used method for the evaluation of the structural performance of pavement systems. In the FWD test, a large weight is raised off the ground and dropped onto a rubber loading pad creating an impulse load representative of the real loading imposed by heavy traffic on the pavement. The excitation produced by the loading sets off waves in the pavement and underlying soil. Deflection time histories are gathered by an array of sensors placed at several nearby locations. The traditional method for interpreting the FWD data to backcalculate structural pavement properties, involves extracting the peak deflection from each displacement trace of the sensors (deflection basin) and matching it through an iterative optimization method to the deflections predicted by a static model of the pavement. This approach is computationally efficient; and when the depths of the layers are known, and their properties are largely homogeneous with depth, the procedure is effective in backcalculating layer properties. However, when the depths are uncertain or when the moduli vary within a layer, the static backcalculation scheme may not yield reliable results.The goal of this study is to investigate the feasibility and effectiveness of using the complete time history of the FWD test to overcome some of the limitations of the static backcalculation procedure, and recover pavement layer moduli distribution and thickness. The problem is also formulated as a numerical minimization problem, where the unknowns are the resilient moduli of thin "computational layers" that discretize the profile. Our initial finding is that this optimization formulation regularized by constraints on the magnitude and spatial gradient of the moduli, coupled with a continuation scheme for imposing the regularization terms, can overcome the ill-posedness nature or the original optimization problem. The computational effort for solving this inverse problem, however, is very significant as it requires repeated calls to the expensive forward problem: an elastodynamic simulation in stiff heterogeneous media. Additional work is needed to speed up the forward problem to be able to perform a more comprehensive evaluation with field data.

Authors:
Turkiyyah,G. M.

Keywords:
research, falling weight deflectometer, weight, evaluation, performance, pavement, systems, traffic, data, moduli, profile, speed

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External Links: http://www.wsdot.wa.gov/research/reports/fullreports/586.1.pdf http://wsdot.wa.gov/Research/Reports/500/586.1.htm

Abstract:
High occupancy vehicle (HOV) lanes, also known as carpool lanes and diamond lanes, are designated for use by carpoolers, transit riders, ride sharers and motorcyclists that meet the occupancy requirement. By restricting access, the HOV lanes benefit users by allowing them to travel the freeway system at a faster speed, thus saving time, and experiencing greater time reliability in comparison to motorists on general purpose (GP) lanes. To accurately evaluate the system's effectiveness, a state policy requires an annual HOV system report to document system performance, examining the HOV lanes' person-carrying capability, travel time savings, and trip reliability benefits in comparison to adjacent GP lanes. HOV lane violation rates are also evaluated. This report describes the results of an extensive monitoring effort of HOV lane use and performance in the Puget Sound area in 2002. It presents an analysis of data collected to describe the number of people and vehicles that use HOV lanes, the reliability of the HOV lanes, the travel time savings in comparison to GP lanes, violation rates and public perceptions. This information is intended to serve as reliable input for transportation decision makers and planners in evaluating the impact and adequacy of the existing HOV lane system in the Puget sound area, and in planning for other HOV facilities. This is volume 1 of a two-volume set. Volume 2 provides an overview of major trends in HOV lane performance by comparing data presented in the 2000 HOV Performance Report.

Authors:
Nee,J., Ishimaru,J. M., Hallenbeck,M. E.

Keywords:
analysis, benefit, benefits, carpool, data, facilities, freeway, GP lanes, high occupancy, high occupancy vehicle, HOV, HOV facilities, HOV lanes, HOV performance, monitoring, occupancy, performance, performance monitoring, planning, policy, public, reliability, research, speed, transit, transportation, travel time, violation, volume

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External Links: http://www.wsdot.wa.gov/research/reports/fullreports/584.2.pdf http://wsdot.wa.gov/Research/Reports/500/584.2.htm

Abstract:
This report documents the development of data collection methodologies that can be used to cost effectively measure truck movements along specific roadway corridors selected by the Freight Mobility Strategic Investment Board (FMSIB.) The intent of this study was to design and test methodologies that could be used to measure the performance of freight mobility roadway improvement projects against benchmarks, or selected standards, which would be used both as part of the project selection process and to report on speed and volume improvements that resulted from completed FMSIB projects. One technology tested was Commercial Vehicle Information System and Networks (CVISN) electronic truck transponders, which are mounted on the windshields of approximately 20,000 trucks traveling in Washington. These transponders are used at weigh stations across the state to improve the efficiency of truck regulatory compliance checks. By using software to link the transponder reads from sites anywhere in the state, the transponder-equipped trucks could become a travel time probe fleet. The second technology tested involved global positioning systems (GPS) placed in volunteer trucks recruited for this project to collect specific truck movement data at 5-second intervals. With GPS data it was possible to understand when and where the monitored trucks experienced congestion. By aggregating this information over time, it was possible to generate performance statistics related to the reliability of truck trips, and even examine changes in route choice for trips between high volume origin/destination pairs. The study found that both data collection technologies could be useful; however, the key to both technologies is whether enough instrumented vehicles pass over the roadways for which data are required. This basic condition significantly affects whether the transponder and GPS technologies will be effective at collecting the data required for any given FMSIB benchmark project . The report also recommends the traffic data that should be collected for a benchmark program and the potential costs of using either data collection technology.

Authors:
McCormack,E. D., Hallenbeck,M. E.

Keywords:
freight movement reliability, truck monitoring, development, data, data collection, methodology, cost, truck, roadway, corridors, freight, freight mobility, mobility, design, performance, speed, volume, commercial vehicle, networks, trucks, Washington, software, travel time, probe, global positioning, global positioning systems, positioning, systems, GPS, congestion, statistics, reliability, condition, traffic, traffic data, program, costs

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Abstract:
The intent of this project was to develop retroreflectivity degradation curves for roadway pavement markings. To accomplish this objective, this study utilized a vehicle-mounted Laserlux retroreflectometer to take measurements on approximately 80 test sections throughout Washington state. The resulting retroreflectivity values from roadways with similar average annual daily traffic (AADT) and environments displayed a significant amount of variability. Best-fit trendlines were extrapolated to determine when each category of paint would fall below a selected minimum threshold of 100 mcd/m2/lux and require repainting.Unfortunately, given the variability of the data observed to date, it may not be possible, even with the collection of more data, to create striping performance predictions that have a high level of statistical confidence. According to that schedule, long line painted markings should be painted at least once a year, and heavy wear, long line pavement markings should be painted at least twice a year.

Authors:
Kopf,J.

Keywords:
degradation curves, Laserlux retroreflectometer, pavement, pavement markings, retroreflectivity, roadway, Washington, Washington state, traffic, environment, data, performance, prediction, line

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External Links: http://www.wsdot.wa.gov/research/reports/fullreports/592.1.pdf http://wsdot.wa.gov/Research/Reports/500/592.1.htm

Abstract:
This research study was conducted to evaluate the in-service performance of existing guardrail end treatments and unrestrained pre-cast concrete barrier in Washington State. For a selected area of the state highway system over a one-year period, local area maintenance personnel were tasked to document incidents, including extent of damage and repair costs, into a database using NCHRP Project 22-13 methodology. Additional information (accident severity, e.g.) from police reports was gathered from the incidents and added to the database. The installation characteristics measured for Breakaway Cable Terminals (BCT) and Slotted Rail Terminals (SRT), along with the related crash data for these devices, showed overall acceptable performance when struck. Review of the incident severities, together with the displacement and damage data on struck barriers in the study area, revealed no significant difference in BCT and SRT performance. The installation, damage, and displacement characteristics examined on struck concrete barrier showed that the pin and loop connections were holding well in incidents, and the barrier displacements during incidents were within the WSDOT design specification for such systems.

Authors:
Igharo,P. O., Murphy,J., Glad,R. W.

Keywords:
performance, guardrail, Washington, Washington state, guardrail end treaments, breakaway cable terminal (BCT), roadside safety, slotted rail terminal (SRT), research, end treatment, precast concrete, concrete, concrete barrier, highway, maintenance, incident, damage, repair, costs, cost, database, methodology, accident severity, data, barriers, WSDOT, design, specification, systems

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External Links: http://www.wsdot.wa.gov/research/reports/fullreports/580.1.pdf http://wsdot.wa.gov/Research/Reports/500/580.1.htm

Abstract:
More extensive use of precast concrete components, which are fabricated off-site and then connected on-site, could allow bridges to be constructed more rapidly. The increased use of precast components in bridges also promises to increase work-zone safety and reduce environmental impacts for bridges that span waterways. This report discusses precast concrete systems that have been used for rapid bridge construction outside of Washington State and evaluates whether they are suitable for use within Western Washington. The report also identifies key features that are important for successful precast concrete system applications. Information on previously used systems was gathered through an extensive review of published literature. Washington State Department of Transportation (WSDOT) design and construction engineers, precast concrete producers, and bridge contractors were also consulted to obtain their input on the positive and negative aspects of applied systems. Most applications have been used in areas of low seismic potential. By contrast, Western Washington is subject to strong earthquakes. Because precast systems contain connections, and connections are typically vulnerable to seismic loading, a qualitative evaluation of the expected seismic performance of each system was deemed necessary. The researchers identified four types of precast concrete superstructure systems: full-depth precast concrete panels, partial-depth precast concrete panels, prestressed concrete multibeam superstructures, and preconstructed composite units. The four systems appear to have acceptable seismic behavior, but there are concerns associated with constructability and durability. Precast concrete substructure systems have received much less attention than have superstructure systems. The use of precast substructure components can provide significant time savings by eliminating the time needed to erect formwork, fix steel, and cure concrete in the substructure. The success of the system depends strongly on the connections, which must hae good seismic resistance, have tolerances that allow easy assembly, and be suitable for rapid construction.

Authors:
Hieber,D. G., Wacker,J. M., Eberhard,M. O., Stanton,J. F.

Keywords:
bridge, bridges, concrete, construction, multibeam superstructures, precast concrete, precast substructures, prestressed concrete, Rapid construction, state-of-the-art, systems, safety, environmental, environmental impact, impacts, span, Washington, Washington state, applications, transportation, WSDOT, design, seismic, earthquake, seismic loading, evaluation, performance, superstructure, prestressed, seismic behavior, constructability, durability, steel, resistance

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External Links: http://www.wsdot.wa.gov/research/reports/fullreports/594.1.pdf http://wsdot.wa.gov/Research/Reports/500/594.1.htm

Abstract:
This research was Phase III of field investigations carried out over 12 years at a test section in southwest Washington State in an effort to quantify the contribution of geotextile separators to the long-term performance of pavement sections. Five different geotextile separators, as well as a control (soil-only) section, were installed in a test section covering two lanes with different base course thicknesses on a low volume but heavily loaded rural highway west of Bucoda, Wash. Phase I evaluated the performance of the separators during construction. Phases II and III were conducted to evaluate the performance of the separators 5 and 12 years after construction, respectively. Field and laboratory tests were conducted on the subgrade, granular base materials, and the geotextiles as part of the effort to correlate the performance of the pavement section to the presence of the geotextile separators. Falling weight deflectometer (FWD) testing was also performed at the site as part of the effort to quantify the performance of the pavement section. The laboratory tests indicated that the geotextiles successfully performed their separation function over the 12-year period. However, the soil-only sections had a minimal amount of intermixing at the base course/subgrade interface, indicating that the separation benefits of geotextiles may not be realized under relatively thick pavement sections. Field density tests indicated that the density of the subgrade in the sections with a geotextile generally increased between construction and the first field investigation, whereas the density of the soil-only sections remained about the same. Similarly, the FWD tests showed that the most significant increase in the subgrade moduli occurred in the first few months following construction. However, the soil-only sections exhibited behavior similar to the sections with geotextiles during the FWD testing, suggesting that for the relatively thick pavement sections, incorporation of geotextiles may not have provided a significant contribution to the overall performance of the section over the 12-year period. Some of the FWD results did suggest that geotextiles might contribute to an increase in the base course modulus over time.

Authors:
Collins,B. M., Holtz,R. D.

Keywords:
base, behavior, benefit, benefits, construction, control, density, falling weight deflectometer, field investigations, geotextile, geotextile separators, highway, materials, moduli, pavement, pavement performance, pavement section, research, rural, separators, subgrade, tests, volume, Washington, Washington state, weight, performance

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External Links: http://www.wsdot.wa.gov/research/reports/fullreports/595.1.pdf http://wsdot.wa.gov/Research/Reports/500/595.1.htm

Abstract:
Cotton duck bearing pads (CDP) are sometimes used to support loads and accommodate movements and rotations at bridge bearings. CDP are preformed elastomeric pads consisting of thin layers of elastomer interlaid with fabric, and they are manufactured under Military Specifications with limited guidance from the AASHTO. The behavior of these CDP bearing pads was experimentally evaluated to establish design models for predicting this behavior, to determine the variation in behavior expected with different bearing pad manufacturers, and to develop design recommendations. This research is a follow-up study of an earlier research program sponsored by Arkansas State University.CDP bearing pads from three different manufacturers were tested, and the test program included dynamic and static (or monotonic) tests of bearings in shear, compression,and rotation. In general, the static tests were used to evaluate strength, stiffness, deformation limits, and general pad behavior. The dynamic tests examined durability and performance under repeated loading and deformation.The results of this test program were used to develop design recommendations, and an appendix includes a draft of proposed wording for modification of the AASHTO LRFD Specifications to include these design recommendations. In addition, a spreadsheet was developed in Microsoft EXCEL to accomplish the calculations necessary to complete the design.

Authors:
Lehman,D. E., Roeder,C. W., Larsen,R., Curtin,K.

Keywords:
cotton duck bearing pads, CDP, bridge bearings, bridge design, loads, bridge, specifications, specification, behavior, design, models, research, program, tests, strength, durability, performance

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External Links: http://www.wsdot.wa.gov/research/reports/fullreports/569.1.pdf http://wsdot.wa.gov/Research/Reports/500/569.1.htm

Abstract:
Floating bridge concrete must be watertight, durable, workable, and must have sufficient cohesiveness to prevent segregation in heavily congested deep walls. The mix design must experience minimal creep and shrinkage to reduce prestress losses, and shrinkage cracking. As a result of recent concrete research, new mixes were created incorporating various quantities of fly ash, silica fume, metakaolin, poly-carboxylate ether superplasticizers, and Caltite waterproofing admixture. This research focuses on concrete with a water binder ratio of 0.33 and a slump in the range of 8 to 9 inches. Workability characteristics of the fresh concrete are analyzed and hardened concrete properties tested in this research are compressive strength, chloride ion permeability, and creep and drying shrinkage properties. It was found that metakaolin was successful in producing mix designs with similar properties as Silica fume modified concrete. Satisfactory strength was achieved through increasing the fly ash and lowering the silica fume contents, though, chloride ion permeability was negatively affected. The removal of silica fume and the inclusion of Caltite decreased the concrete’s resistance to chloride ion permeability and produced concrete that failed to attain the required 28-day ultimate compressive strength of 6500 psi. The second part of this study focuses on developing an experimental setup to evaluate products and construction methods to help prevent water leakage through construction joints in pontoon floating bridges. A pressure system was used to apply significant pressures to concrete test specimens containing a construction joint. Different products and construction methods were used in constructing the joints to determine the most effective methods for preventing water penetration in the field. The testing results have shown compaction effort is the most important factor in water leakage through a joint. Increased compaction in laboratory specimens leads to less water leakage through construction joints. Product selection was ineffective in preventing water leakage if concrete compaction was inadequate.

Authors:
Itani,R., Masad,E., Balko,B., Bayne,B.

Keywords:
concrete, performance, fly ash, silica fume, metakaolin, polycarboxylate, caltite, creep, shrinkage, compressive strength, permeability, construction joint, leakage, waterstop, accident rates, compaction, watertight

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Abstract:
This summary report presents an overview of the level of traveler usage (e.g., how many vehicles use the freeways) and travel performance (e.g., how fast they are traveling, where and how often congestion ocurs) on the principal urban freeways in the central Puget Sound area. The freeways studied in this project are managed by the Washington State Department of Transportation (WSDOT) using its FLOW system, a coordinated network of traffic monitoring, measuring, information dissemination, and control devices that operates on urban state and Interstate highways in the central Puget Sound region. Data presented in this report were collected by the WSDOT's freeway surveillance system. The project that led to this report is intended to meet two separate purposes: 1) to enhance WSDOT's ability to monitor and improve its traffic management efforts on Seattle-area highways, and 2) to provide useful information to the public and decision makers about the status of the freeway system's operational performance. This report is primarily intended to meet the second of these objectives. However, the software developed to assist in freeway data analysis for this project and many of the graphics presented in this report are directly applicable to the first objective.

Authors:
Avery,R. P., Ishimaru,J. M., Nee,J., Hallenbeck,M. E.

Keywords:
analysis, Archived Data User Services (ADUS), congestion, congestion monitoring, control, data, flow, freeway, freeway performance, highway, information dissemination, ITS, management, monitoring, performance, public, research, surveillance, traffic, traffic management, traffic monitoring, transportation, urban, Washington, Washington state, WSDOT

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External Links: http://www.wsdot.wa.gov/research/reports/fullreports/563.1.pdf http://wsdot.wa.gov/Research/Reports/500/563.1.htm

Abstract:
Studded tires have generated much controversy over the years; a number of states have banned them, while others, including Washington, have restricted their use and passed legislation to require lighter-weight studs. This report reviews recent studies that have addressed the performance and safety of the current generation of studded tires as well as the new "studless" winter tires on late-model vehicles. The well-documented correlation between studded tires and pavement wear was not the focus of this work.The issues surrounding studded tire performance and safety are complex. From the standpoint of traction alone, studded tires, when new, often provide some benefit over the other tire types on ice-covered roads when the temperature is near f reezing. However, the advent of the new studless tires has diminished the marginal benefit, and recent studies suggest that the infrequent, narrow range of conditions necessry for benefit from studded tires may not outweigh their detrimental effect on tracton in dry or wet conditions on certain pavement types. In addition, a host of primary and secondary safety factors are related to studded tire use, many of which are very difficult to quantify, including facets of driver behavior and safety perception.

Authors:
Scheibe,R. R.

Keywords:
studded tire, traction, performance, safety, winter, research, Kirkland

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External Links: http://www.wsdot.wa.gov/research/reports/fullreports/551.1.pdf http://wsdot.wa.gov/Research/Reports/500/551.1.htm

Abstract:
This research project was an effort to improve our understanding of the internal stress-strain distribution in GRS retaining structures. Our numerical modelling techniques utilized a commercially available element program, FLAC (Fast Lagrangian Analysis of Continua). In this research, we investigated and appropriately considered the plane strain soil properties, the effect of low confining pressure on the soil dilation angle, and in-soil and low strain rate geosynthetic reinforcement properties.Modeling techniques that are able to predict both the internal and external performance of GRS walls simultaneously were developed. Instrumentation measurements such as wall deflection and reinforcement strain distributions of a number of selected case histories were successfully reproduced by our numerical modeling techniques. Moreover, these techniques were verified by successfully performing true "Class A" predictions of three large-scale experimental walls.An extensive parametric study that included more than 250 numerical models was then performed to investigate the influence of design factors such as soil properties, reinforcement stiffness, and reinforcement spacing on GRS wall performance. Moreover, effects of design options such as toe restraint and structural facing systems were examined. An alternative method for internal stress-strain analysis based on the stress-strain behavior of GRS as a composite material was also developed. Finally, the modeling results were used to develop a new technique for predicting GRS wall face deformations and to make recommendations for the internal stability design of GRS walls.

Authors:
Holtz,R. D., Lee,W. F.

Keywords:
analysis, behavior, design, experimental, FLAC, geosynthetic, geotechnical, materials, modeling, models, performance, prediction, pressure, program, reinforcement, research, retaining wall, retaining walls, stability, structures, systems, walls

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External Links: http://www.wsdot.wa.gov/research/reports/fullreports/532.1.pdf http://wsdot.wa.gov/Research/Reports/500/532.1.htm

Abstract:
In this study, the performance of five typical mix designs from four different regions in Washington state is assessed. The performance characteristics that are evaluated include four durability properties: freeze-thaw durability, scaling resistance, abrasion resistance, chloride penetration, and one strength-related property: compressive strength.Determination of the current level of performance of existing concrete mixes is the first step toward fully implementing performance-based specifications. Knowing the level of durability of existing mix designs will give WSDOT a starting point in defining new levels of durability for higher performance mixes. Previously, the selection of appropriate mix designs was based solely on the flexural or compressive strength of the mix. The results of this study enable mix designs to be selected by matching the performance grade with exposure conditions.A map of the state of Washington outlining freeze-thaw zones is presented to indicate exposure conditions. This may be used to match pavement performance grades with actual field conditions. Recommendations based on experimental findings and the literature review are provided for improving the durability of the mixes.

Authors:
Masad,E., James,L.

Keywords:
concrete, performance, freeze-thaw, Scaling, abrasion, permeability, research

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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:
The Seattle Wide-area Information for Travelers (SWIFT) Operational Test was intended to evaluate the performance of a large-scale, urban Advanced Traveler Information System (ATIS) deployment in the Seattle area. With the majority the SWIFT system completed by June 30,1996, the SWIFT Field Operational Test (FOT) evaluation was conducted from July 1, 1996 through September 20, 1997. The unique features of the SWIFT ATIS included the provision of information for multiple transportation modes, the delivery of this information using three different devices and the use of FM sideband as the primary communications medium. A total of 690 system users were recruited during the course of the study, including 520 Seiko Message watch users, 90 users of the Delco in-vehicle-navigation device and 80 users of the SWIFT portable computers.Purpose of Test. The SWIFT Consumer Acceptance Study was one of five component studies to the overall system evaluation. This report details the findings for the SWIFT Consumer Acceptance Study based on the evaluation objectives that were identified in the SWIFT Evaluation Plan (1 995). The primary objectives of the SWIFT Consumer Acceptance Study were to assess the following:Importance of traveler information in travel planningUsefulness of SWIFT traveler information in travel planningMinimum set of user services and device features required to provide viable productand servicesUser perceptions of SWIFT device usefulnessWillingness-to-pay for different services.User perceptions of changes in travel convenience and efficiencyUser perceptions of changes in traffic congestion, air quality, energy consumption,and safety.Additional SWIFT Consumer Acceptance Study objectives, conducted in support of the SWIFTArchitecture Study, were to assess the following:SWIFT system reliability from a user perspectiveSWIFT system availability from a user perspective.Methods. A variety of data-collection efforts were completed, including questionnaires, focus groups and telephone interviews. The questionnaires contained items that addressed objectives set out in the evaluation plan. The focus groups were conducted with small groups of users to obtain qualitative impressions from a smaller subset of users who were encouraged to speak openly and share their perceptions with other users. The SWIFT Consumer Acceptance Study focused on measurement and analysis of user perceptions toward SWIFT system usefulness and performance. No attempt was made to quantify the system level impacts of SWIFT services on congestion, air quality, energy consumption or safety in the Seattle region. Rather, the assessment of system-level transportation impacts was limited to examining subjective data (e.g., traveler's perceptions) collected from users and determining whether these perceptions were consistent with a benefit.Perceptions of Importance of Traveler In formationResults indicated that SWIFT users tended to place a high degree of importance on incident and congestion-related information in travel planning. Incident location and duration information was rated quite high in importance along with general traffic congestion information. For the group as a whole, information concerning bus schedule and route information and bus-location information was rated very low in importance, although these ratings were much higher in those users that actually used the bus. This was consistent with the automobile dependence reported by the group, and suggests that information concerning non-automobile options would not be used by the automobile-dependent group. Since users of the SWIFT portable computer were recruited from among transit users, this group generally rated transit information higher than other device users groups. However, the importance of this information was not as high as congestion and incident-related information. Receipt of various general-information messages was not rated very high in importance by questionnaire respondents, with the exception of weather, sports and news items. Most SWIFT respondents indicated that the receipt of financial and other environmental information was not important. Of course, from a transportation-impact point of view, the receipt of these general information messages was inconsequential. However, if device users were attracted by thesemessages it may make such services commercially viable to augment any potential benefitperceived by users through the receipt of travel-related information.Perceptions of S WIFT Traveler In formation UsefulnessUsers tended to view the messages they received from the SWIFT systems as accurate, reliable,timely, easy to understand and useful. Among device types, respondents representing users of the Seiko Message Watch expressed concern with the timeliness of incident-related messages. In addition, these respondents tended to rate ease of understanding lower than other user groups. Users of the Delco in-vehicle-navigation devices and SWIFT portable computers experienced problems in receiving personal-paging messages and these problems were reflected in respondent ratings. The map-based display provided by the SWIFT portable computer resulted in generally higher ratings for this device over other devices in understanding incident location and the nature of congestion. Seiko Message Watch users reported difficulty in understanding the extent of expected delay as well as the nature of congestion, while Delco in-vehicle-navigation device respondents reported difficulty in understanding the period of time for which a message applied. Generally speaking, SWIFT participants endorsed a wide-range of improvements to messages provided by the SWIFT system. Most seemed to consider the operational test as a suggestion of what might be possible, rather than a demonstration of a final product. Among Seiko Message Watch users, respondents expressed a desire for improved timeliness of messages as atop priority.

Authors:
Trombly,J., Wetherby,B., Dixson,A.

Keywords:
Acceptance, air quality, analysis, Assessment, ATIS, availability, bus, computer, congestion, congestion information, Consumer, data, data collection, Energy, environmental, evaluation, group, impact, impacts, improvement, incident, interviews, Miscellaneous Library, objectives, performance, planning, portable computer, quality, reliability, safety, seattle, Study, SWIFT, System, systems, traffic, traffic congestion, transit, transportation, travel, traveler information, urban

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Abstract:
This report documents the rehabilitation of a faulted Portland cement concrete pavement with epoxy coated dowel bars. The dowel bars were installed parallel with centerline at each joint to reestablish panel to panel interlock. The construction project also included the trial installation of tied PCC shoulders as a means of stabilizing the panels. Diamond grindling was also included in the contract to bring the retrofit pavement back to a smooth longitudinal profile.Early performance results indicate that the retrofit dowel bars are performing better than the tied shoulders with regard to preventing the reoccurrence of faulting.

Authors:
Pierce,L., Korynta,A.

Keywords:
concrete, construction, dowel bar, Epoxy, faulting, pavement, PCC, PCCP rehabilitation, performance, portland cement concrete, profile, project, rehabilitation, retrofit

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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:
This first report documents some of the more fundamental features of the Washington State Pavement Management System (WSPMS). Included is an overview of Pavement management principals. Recent additions to the WSPMS include the rehabilitation scoping technique and revised pavement rating scores. These are documented in the report.

Authors:
Mahoney,J. P., Kay,R. K., Jackson,N. C.

Keywords:
pavement, pavement management, performance, pavement policy

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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:
A short, one year performance evaluation was made of four crack sealing products. The products: (1) CRF manufactured by the Golden Bear Division of Witco Chemical Corporation; (2) Flex-a-Fill manufactured by Deery Oil; (3) RoadSaver 221 manufactured by Crafco Incorporated; and (4) a sand slurry mixture designed by the Washington State Department of Transportation.The two rubber-asphalt products, Flex-a-Fill and RoadSaver 221, performed better that the other two products, which used an emulsified cement as a base.

Authors:
Erickson,D. E.

Keywords:
base, crack sealing, effectiveness, emulsified asphalt, evaluation, mixture, performance, performance evaluation, Rubber-asphalt, transportation, Washington, Washington state

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Abstract:
In order to provide for a preload fill in an area of limited right-of-way, the Washington State Department of Transportation designed and supervised the construction of a geotextile reinforced retaining wall 12.6m (41.3 ft) high. Because the wall supported a surcharge fi11 more than5 m (16 ft.) in height and was significantly higher than any previouslyconstructed wall of i t s type, an extensive program of instrumentationof the geotextile reinforcement and measurement o f the wall movementswas instituted. The paper describes the wall design and construction,1)purpose and objectives of the instrumentation program, instrumentation . .selection and installation, and results of the monitoring. The measureddeflections and reinforcement strain were low, and overall wall performance was excellent.

Authors:
Allen,T. M., Christopher,B., Holtz,R. D.

Keywords:
construction, design, geotextile, Geotextiles, monitoring, objectives, performance, program, reinforcement, retaining wall, surcharge, transportation, walls, Washington, Washington state

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External Links: http://wsdot.wa.gov/Research/Reports/200/257.1.htm

Abstract:
Bridge expansion joints pose a special problem in the Washington State Department of Transportation (WSDOT) bridge deck management system. These devices are subject to repeated heavy dynamic loading, and premature failure has occurred in many cases. It is WSDOT policy, as part of the Bridge Deck Management System, to make expansion joints watertight in order to reduce the potential of substructure corrosion induced by roadway deicing salts and other contaminants.Expansion joint seals play an important role in keeping expansion joints watertight. A relatively new material, Evazote 50, looks promising in its performance characteristics as an expansion joint seal. It is able to accommodate considerable joint movement, its durability and corrosion resistant properties are excellent, and it is resistant to absorption of oils and greases. The purpose of this experimental project is to gain knowledge about the material\'s effectiveness over time and to gain knowledge about field installation techniques. It was very beneficial to have the manufacturer\'s representative on the job during installation. This was required by special provision and is a practice that should be continued on future projects.In-place performance will determine acceptance of Evazote 50 for general use.

Authors:
Roper,T. H., Henley,E. H. Jr

Keywords:
absorption, bridge, bridge deck, bridge deck rehabilitation, corrosion, Deck, durability, effectiveness, expansion joints, experimental, in-place, ITS, Joints, management, management system, performance, policy, roadway, salt, transportation, Washington, Washington state, WSDOT

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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:
Washington State has approximately 700 bridge decks that may require a latex modified concrete (LMC) overlay in the next 12 to 15 years. The microsilica concrete overlay is seen as a possible alternative to the increasingly expensive latex modified concrete.A microsilica modified concrete overlay was placed on Bridge 5/718W in Skagit County.The bridge is a concrete box girder structure with 8,100 square feet of deck area. The ADT on this bridge is 9,150 vehicles per day.The minimum overlay thickness was 1% inches. Superplasticizer was added to the mix. The concrete was mixed in a conventional batch plant with the technical representative from the microsilica supplier providing assistance. The microsilica modified concreteoverlay was finished and cured as prescribed by WSDOTts specification for LMC overlays.The microsilica was supplied as a slurry. Force 10,000, produced by W. R. Grace and Company, Cambridge, Massachusetts, was the source of the microsilica.The long-term performance evaluation of the microsilica-modified concrete will be based on a direct comparison with the LMC overlay to be constructed on Bridge 5/71SE. Both bridges are of similar construction, have the same deck area and ADT, and have existing decks with similar levels of chloride contamination. Both overlays were constructed under the same contract.

Authors:
Roper,T. H., Henley,E. H. Jr

Keywords:
Alternative, bridge, bridge deck, bridge deck overlay, bridge deck repairs, bridge decks, bridges, chloride, concrete, concrete additives, construction, contamination, Deck, evaluation, latex modified concrete, microsilica concrete, overlay, overlays, performance, performance evaluation, silica fume, specification, Washington, Washington state

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Abstract:
This report describes the construction of an experimental section of asphalt concrete pavement overlay which contained the additive carbon black. A long term evaluation of the overlay seeks to determine if there is a significant difference in performance between it and an adjacent control section of pavement which contains no additive.Preliminary laboratory results indicate that the viscosity/temperature curve for the carbon black asphalt binder has been altered in a way that the temperature susceptibility of the pavement is decreased.

Authors:
Livingston,J.

Keywords:
additive, asphalt, asphalt concrete, Asphalt Concrete pavement, Carbon black, concrete, construction, control, evaluation, experimental, overlay, pavement, performance, susceptibility, temperature, terperature susceptibility

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Abstract:
Three types of stripping materials installed in recessed grooves are evaluated for reflectivity and durability. Initial performance evaluations have two of the materials showing very little wear and providing good daytime delination but marginal nighttime delineation. The other material is showing considerable damage in the form of cracking and spalling and is providing good nighttime delineation but only marginal daytime due to the loss of material.

Authors:
Deer,R., Mansfield,C.

Keywords:
cracking, damage, delineation, durability, evaluation, grooves, lane lines, line, materials, performance, performance evaluation, reflectivity, stripping, traffic

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Abstract:
The WSDOT PMS database was used to develop regression equations for three pavement surface types: bituminous surface treatments, asphalt concrete and portland cement concrete. The primary regression equations developed were to predict Pavement Condition Rating(PCR) which is a measure of the pavement surface distress (ranges from 100 (no distress) to below 0 (extensive distress)). Overall, the equations fit the data rather well given the expected variation of pavement performance information. The relative effects of age (time since construction or reconstruction) were illustrated for the three surface types.

Authors:
Mahoney,J. P., Kay,R. K., Jackson,N. C.

Keywords:
pavement PCC, pavement, performance, statistics, regression, equations

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Abstract:
As part of the pooled fund research project, the Washington State Department of Transportation was selected to field-test approximately 100 tons of Calcium Magnesium Acetate (CMA) to evaluate its potential as a deicing chemical with direct comparison to salt (Sodium Chloride) and Urea. Evaluation included all aspects of storage, handling, use, and performance. CMA was applied whenever necessary at each test site, using the same application rates as presently used for salt. Typical equipment consisted of front dump trucks with the spinner ahead of the rear axle, and rear discharge hopper trucks. All equipment was used without modification.The use of CMA at the beginning of a storm reduced the amount of bonding of snow to the roadway surface. This effect of keeping the roadway surface bare for longer periods of time reduced the cost of snow fighting. This was accomplished with chemical application rate of 125 Ibs. per lane mile.The addition of sand to CMA reduced the problems of dust, caking and uneven distribution. The sand provided moisture and weight to the application resulting in a smoother, more even distribution. CMA spread above was excessively dusty creating problems in the spreading and distribution. CMA is slower to react on compact snow and ice than salt or Urea. This delay in reaction time was not considered a handicap in the overall snow fighting procedure.The conclusion was that CMA shows promise as a deicing-melting chemical. The problems of dust, light-weight and brittleness need further work and may be significantly alleviated by development of a hydrated compound.

Authors:
Ernst,D. D.

Keywords:
Alternative, axle, chloride, cost, Deicing (CMA Research), development, evaluation, field test, ITS, lightweight, performance, research, roadway, salt, snow, transportation, truck, trucks, Washington, Washington state, weight

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Abstract:
Three joint sealant materials were installed in a special test section of a Portland cement concrete pavement rehabilitation project located on I-90 near Hyak, Washington. The three materials (1) Dow Corning 888 Silicon; (2) Crafco RoadSaver 231; and (3) Crafco Roadsaver 221 will be monitored for a period of three years to determine their service life and cost-effectiveness.Initial inspections indicate very good performance for all three materials although problems with one area of the silicon sealant test section required a modification of the standard installation procedures to produce a satisfactory final product.

Authors:
Anderson,K. W.

Keywords:
concrete, inspection, Joints, materials, pavement, performance, portland cement concrete, rehabilitation, Washington

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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:
Asphalt mixes modified with the addition of reclaimed rubber granules (PlusRide) and polyester fibers (BoniFibers) were used in a 0.12-ft overlay of a badly distressed section of AC pavement. The distress consisted of transverse and longitudinal cracking which was reflecting through from the underlying old PCC pavement and severe alligator cracking which was an age related fatigue problem. A section of standard Class B dense graded ACP was also put down to serve as a control section for judging performance.The three sections are to be monitored over a period of three years to determine the effectiveness of the asphalt additive products in preventing the reflection of the distresses noted in the underlying pavementfrom showing through in the overlay. The first year inspection revealed that the PlusRide section was showing some longitudinal cracking over the old PCC lane edge. The BoniFibers section was also showing the same longitudinal distress over the lane edge of the underlying PCC plus a small amount of transverse cracking.

Authors:
Anderson,J. L.

Keywords:
additive, Alligator Cracking, asphalt, asphalt pavement mixtures, Bonifibers, control, cracking, Distress, effectiveness, evaluation, fatigue, inspection, overlay, pavement, PCC, performance, PlusRide, polyester, Polyester Fibers, reflective crack prevention, rubber

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Abstract:
This study involved an in-depth evaluation of the Washington State Department of Transportation highway data development and analysis activities. It developed statistically-based procedures and recommendations for a streamlined highway data collection program. Opportunities to reduce manpower and equipment costs, streamline work activities, improve the quality of data collection and provide accurate and timely data for the various users were identified. Given the focus on highway data, the major effort was devoted to the Department's traffic counting program. However, many data items and programs were considered, with the following receiving particular attention: traffic volume counting, including estimation of annual average daily traffic at any location throughout the state highway system; associated seasonal, axle and growth factors; vehicle classification; truck weights; and the relationship between the statistical sampling requirements recommended for these items and those associated with the FHWA Highway Performance Monitoring System in the state.

Authors:
Ritchie,S. G., Hallenbeck,M. E.

Keywords:
analysis, Annual, axle, cost, costs, data, data collection, developed, development, equipment, evaluation, highway, monitoring, performance, performance monitoring, program, quality, sampling, seasonal, Study, System, traffic, traffic counting, transportation, truck, vehicle classification, volume, Washington, Washington state, weight, weights

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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:


Authors:
Mahoney,J. P., Jackson,N. C.

Keywords:
asphalt, pavement, design, performance

Abstract:
The first phase of a three-phase research investigation of cut slope design criteria for southeastern Washington loess has been completed. A literature review of engineering properties of loess from other locales and design criteria applied by various state transportation departments were conducted. A1so, a preliminary field investigation was made to collect representative soil samples and record failure mechanisms. Past research has revealed that proper drainage control in combination with water content and gradational characteristics, are the primary factors influencing cut slope performance in loessial soils. Analysis of 40 soil samples collected during the field study, demonstrate a close similarity between southeastern Washington loess and deposits from the central United States. Although physical properties are similar, differing climates produce a disparity in failure mechanisms between Midwestern and southeastern Washington loessial deposits.

Authors:
Higgins,J. D., Fragaszy,R. J., Beard,L. D.

Keywords:
analysis, control, criteria, cut slope, design, design criteria, development, drainage, erosion, loess, performance, research, review, slope stability, soil, state-of-the-art, Study, transportation, Washington

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Abstract:
The study is reported in two volumes. The first volume summarizes the state-of-the-art on pavement overlay design and presents a research plan to develop an overlay design procedure for the Washington State Department of Transportation (WSDOT) The second volume contains an annotated bibliographyof significant pavement overlay literature published since 1968.The state-of-the-art review presented in Volume I addresses pavement evaluation using nondestructive testing and subjective ratings. These are discussed along with the topics of traffic and seasonal variations. Pavement overlay design concepts are identified and discussed. A research plan is presented forthe development of a pavement overlay design system for WSDOT.

Authors:
Newcomb,D. E., Bubushait,A. A., Mahoney,J. P., Sharma,J.

Keywords:
design, development, evaluation, nondestructive testing, overlay, pavement, pavement evaluation, performance, research, review, seasonal, seasonal variation, seasonal variations, state-of-the-art, Study, System, traffic, transportation, volume, Washington, Washington state, WSDOT

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Abstract:
This report is presented in two volumes. The first volume summarizes the Final Report Sept. 15 - Dec. 15, 1983 14. Sponsoring Agency Code state-of-the-art on pavement overlay design and presents a research plan to develop an overlay design procedure for the Washington State Department of Transportation (WSDOT) . The second volume contains an annotated bibliography of significant pavement overlay 1iterature pub1ished since 1968.The state-of-the-art review presented in Volume I addresses pavement evaluation using nondestructive testing and subjective ratings. These are discussed along with the topics of traffic and seasonal variations. Pavement overlay design concepts are identified and discussed. A research plan is presented for the development of a pavement overlay design system for WSDOT,

Authors:
Newcomb,D. E., Bubushait,A. A., Mahoney,J. P., Sharma,J.

Keywords:
agencies, design, development, evaluation, nondestructive testing, overlay, pavement, pavement evaluation, performance, research, review, seasonal, seasonal variation, seasonal variations, state-of-the-art, System, traffic, transportation, volume, Washington, Washington state, WSDOT

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Abstract:
This report examines major issues, concepts and methods of bus transit performance evaluation and suggests procedures and guidelines for internal and external monitoring in Washington State. In support of suggested procedures, data analysis on six years of operational and financial characteristics of Washington State systems, 1979-80 Section 15 data, and collected samples of small community/rural systems from other states was conducted. The major objective of the analysis was to test methodologies for developing and assessing transit peer groups\" relative to size and scale of operations, and prior to comparative within-group evaluation. The methodology entailed employing cluster analysis using up to 10 variables depicting service design and distribution. Two key variables were population and line miles. Problems were encountered in using Section 15 data. Due to its use of urban area, as opposed to service area population, clear distinctions of operating environments could not be determined. Thus, cluster groupings using Section 15 data were inconclusive. Cluster State systems (1980) were satisfactory and following additional verification, a suggested \"peer group\" classification for Washington State was recommended. The seven group types ranged in size from a rural regional (<40,000 population) to metropolitan (<1,000,00 population). Values for 8 efficiency and effectiveness indicators were used to assess \"peer group\" trends in performance in Washington over a five-year period (1976-80). Comparative evaluations of individual systems were not made. Despite only partial success in determining \"peer groups\", the study does identify methods and procedures for assisting in external and internal performance evaluation.

Authors:
Kelly,W. J., Rutherford,G. S.

Keywords:
peer group evaluation, analysis, bus, bus transit, cluster analysis, data, data collection, design, effectiveness, efficiency, environment, evaluation, group, indicator, indicators, Issues, ITS, line, methodology, methods, monitoring, Operating, performance, performance evaluation, performance measures, performance standards, population, rural, section 15 data, Study, System, systems, transit, urban, Washington, Washington state

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Abstract:
This report describes the pavement management system developed by WSDOT staff over a period of five years. Both project-level and network-level pavement management are represented within the four broad areas of data processing which combine to constitute the foundation of the system.The design of a pavement data file is laid out together with the process of assembling it. Also shown are the methods used to analyze and convert the file data from pavement condition ratings to pavement performance curves for each project. The performance curves are then used, together with appropriate cost data, to determine the most cost-effective type and time to fix. The network-level program then summarized the need work for each year of a rehabilitation program. Mean are provided for adjusting the program to fit budget constraints or minimum acceptable levels of average pavement condition.It is concluded that the system, operating on biennial pavement condition ratings, provides a good solid framework for orderly analysis to estimate the economic benefits of the type, timing, and sequence of rehabilitation activities applied to a pavement.

Authors:
Nelson,Thomas L., LeClerc,R. V.

Keywords:
analysis, benefit, benefits, condition, cost, data, design, developed, development, foundation, framework, management, management system, methods, Operating, pavement, pavement condition, pavement data file, pavement management, pavement performance, performance, program, project, rehabilitation, System, Washington, Washington state, WSDOT

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Abstract:
This report describes the pavement system developed by staff over a period of five years. Both project-level and network-level pavement are represented within the four broad areas of data processing which combine to constitute the foundation of the system. The design of a pavement data file is laid out together with the process of assembling it. Also shown are the methods used to analyze and convert the file data pavement condition ratings to pavement performance curves for each project. The performance curves are then used, together with appropriate cost data, to determine the most cost-effective type and of fix. The network-level program then the needed work for each year of a rehabilitation program. Means are provided for adjusting the program to fit budget constraints or acceptable levels of average pavement condition It is concluded that the system, operating on biennial pavement condition ratings, provides a good solid framework for orderly analysis to estimate the economic benefits of the type, timing, and sequence of rehabilitation activities apply to a pavement.

Authors:
Nelson,Thomas L., LeClerc,R. V.

Keywords:
analysis, benefit, benefits, condition, cost, cost effective, data, design, developed, development, foundation, framework, management, management system, methods, Operating, pavement, pavement condition, pavement data file, pavement management, pavement performance, performance, program, project, rehabilitation, System, Washington, Washington state, WSDOT

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Abstract:
This report provides a summary of a laboratory study on sulfur extended asphalt paving mixtures. The following major features were included in the study: 1.Design of laboratory-experiment which included the use of mixtures which contained various amounts of sulfur, two viscosity levels of asphalt cement, and two of aggregate (basalt and granite).2. Evaluation of mixture design methods (Hveem and Marshal ). 3. Determination of optimum binder contents.4. Evaluation of mixture durability and aging characteristics.5. Development of revised mixture design criteria.

Authors:
Mahoney,J. P., Lary,J. A., Balgunaim,F., Lee,T. C.

Keywords:
aggregate, aging, asphalt, criteria, design, design criteria, development, durability, evaluation, extended asphalt, methods, mixture, performance, stiffness, Study, sulfur, viscosity

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Abstract:
This summary report overviews two previously issued study reports. One report assesses the availability and pricing of sulfur with respect to sulfur extended asphalt (SEA) paving mixtures. The second study report concerned a laboratory oriented testing program which was principally used to examine the durability and aging characteristics of SEA paving mixtures.

Authors:
Mahoney,J. P.

Keywords:
aging, asphalt, asphalt pavement, availability, demand, durability, evaluation, Executive, Executive Summary, extended asphalt, mixture, pavement, pavement evaluation, performance, pricing, program, Study, sulfur, supply

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Abstract:
This report summarizes the placement and performance of sulfur extended asphalt (SEA) paving mixtures at a highway test site (SR 270) near Pullman, Washington. The report includes a summary of the mixture and structure designs and construction details. This is followed by a discussion of the data collection and analysis accomplished over a three year evaluation period (1979 - 1982). A major experimental feature of the study was the use of 0/100 (conventional asphalt concrete), 30/70 and 40/60 SEA binder ratios (sulfur/asphalt ratios are expressed as weight percents) in the experimental paving mixtures.

Authors:
Mahoney,J. P.

Keywords:
analysis, asphalt, asphalt concrete, asphalt pavement, concrete, construction, data, data collection, data collection and analysis, design, evaluation, experimental, extended asphalt, highway, mixture, pavement, pavement performance, performance, Study, sulfur, Washington, weight

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Abstract:
This summary report provides an overview of the performance of sulfur extended asphalt (SEA) paving mixtures at the WSU Test Track (Pullman, WA). A brief description of the mix designs, pavement structural design, test track loading apparatus and test pavement configurations is followed by a description of selected test track data (accelerations, temperatures and stain measurements). Finally, a description of the fatigue relationships developed from the WSU Test Track data is presented. Included are laboratory fatigue results.

Authors:
Mahoney,J. P.

Keywords:
911, asphalt, asphalt pavement, construction, data, design, developed, evaluation, Executive, Executive Summary, extended asphalt, fatigue, mixture, pavement, pavement evaluation, pavement performance, performance, sulfur, temperature, test track

Abstract:
This executive summary overviews the placement and performance of sulfur extended asphalt (SEA) paving mixtures at a highway test site (SR 270) Width3Width8608Width3Width8608 near Pullman, Washington. This is the sixth and last report of this study.

Authors:
Mahoney,J. P.

Keywords:
asphalt, asphalt pavement, Executive, Executive Summary, extended asphalt, highway, mixture, pavement, performance, Study, sulfur, Washington

Abstract:
The purpose of the report is to present major concepts of transit performance evaluation and suggest procedures and guidelines for internal and external performance monitoring in Washington State.

Authors:
Kelly,W. J., Rutherford,G. S.

Keywords:
bus transportation, data collection and analysis, evaluation, Interim, methodology, monitoring, performance, performance evaluation, performance measures, performance monitoring, System, transit, Washington, Washington state

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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:
This report covers the initial 15 months of effort to review the literature, select a prototype site, compare the performance of several automatic sampling devices, and install a prototype sampling site on 1-5 north of Seattle .

Authors:
Horner,R. R., Burges,S. J., Ferguson,J. F., Mar,B. W., Welch,E. B.

Keywords:
highway, highway runoff, Interim, monitoring, performance, review, runoff, sampling, seattle, Water Pollutants, Washington State Monitoring

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Abstract:
Evaluation of pavement patching materials was accomplished by simulating potholes in the surface, repairing the holes and subjecting them to traffic loadings. Loadings were applied utilizing the Pavement Test Facility, which applies truck simultaneously. Measurements of strength resulted in a comparative evaluation. tires was determined. Tire and various passenger car tire .types s skidding potential and pavement performance. Tread wear and protrusion of studs in the tires was determined.

Authors:
Cook,John C.

Keywords:
evaluation, facilities, materials, pavement, Pavement Patching Material, Polishing, Skidding Potential, Studded Tires, Garnet Impregnated Tires, pavement performance, performance, strength, studs, test track, tire, tires, traffic, truck

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Abstract:
The porous walled resonating chamber, a type of breakwater, is investigated as a means of reducing reflected waves from structures subjected to random wind generated waves in deep water. Extending laboratory monochromatic studies to a full-scale apparatus appended to a floating bridge allows assessment of scale factors and the effects of random waves on the predicted performance of thedevice as a linear damped oscillator . The full-scale device is shown to be frequency selective at a frequency precisely corresponding to the predicted resonance of the system. The forces, measured on the porous wall, are lower than predicted and the device completely eliminates the problem of wave runuponto the bridge roadway. The method of evaluating the energy attenuation by the breakwater incorporates spectral analysis of digitized data recorded at fixed locations equidistant in front of the chamber and at a remote station away from the influence of the breakwater. Analysis demonstrates that the time average energy density at a fixed location where incident and reflected waves co-exist is influenced not only by the wave amplitudes, as expected, but also by the product of the amplitudes and a function of the phase angle. The chamber effects a change in the random phase angle during reflection , producing a different effective distance of wave travel to the fixed location and thus negating quantitative analysis of the energy dissipation.

Authors:
Richey,E. P., Morden,D. B., Hartz,B. J.

Keywords:
analysis, Assessment, attenuation, Breakwater, bridge, data, density, Energy, floating bridge, forces, incident, performance, roadway, structures, travel, Wave attenuation, wind

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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 some data obtained from testing twenty-two different types of overlays on three concentric tracks at the G.A. Riedesel Pavement Testing Facility at Washington State University. Six different passenger winter tires were tested, including unstudded, a garnet dust snow retread, and four different types of studs. The data represents a testing period from November 20, 1972 to February 20, 1973 and a total 300,000 revolutions, that is 900,000 wheel applications on the inside track and 300,000 wheel applications on the outside track.The results reveal that the different polymer, concretes show the least wear, and that rubber additives improved the performance of some of the asphalt concrete overlays. The type #2 stud continually showed less wear than the other types of studs. Comparisons with the previous ring reveals that the present ring overlays showed less wear, and that stud protrusions are much less. A comparison and discussion of the results from both rings a t this wheel application range is presented. The results from the present data are also discussed. The results are tentative and may change as the present test continues.

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

Keywords:
applications, asphalt, asphalt concrete, concrete, concrete overlays, data, effects, facilities, Interim, overlay, overlays, pavement, Pavement overlays, performance, Phase II, polymer, rubber, snow, Studded, studded tire, studs, tire, tires, Washington, Washington state, winter

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Abstract:
The purpose of this study was to investigate the acoustic effects of two topping materials used on bridges in the Seattle area. One material was applied to the bridge on Interstate-5 which crosses the Duwamish River. It is an English product called Sprag-Grip which is supposed to have very good anti-skid properties, as well as the ability to stick to the road in thin layers thus making it suitable for the repair of worn surfaces. The other material is an epoxy -asphalt mixture which was applied to some sections of the Evergreen Point Floating Bridge over Lake Washington, particularly over sections where worn grating was causing excessive noise. Hopefully, this substance will be capable of long-term sticking in relatively thin layers. Of the two materials, it was found that the epoxy-asphalt topping on the Evergreen Point Floating Bridge was by far the quieter, and, at least as newly applied, proved to be very quiet at the road/tire interface. It is likely that this good acoustic performance is due to the smoothness of the surface rather than directly to the fact that the material contains epoxy. The role of the epoxy would be as an adhesive and to resist wear so that its original acoustic performance could be maintained for a considerable length of time. Spray-Grip, on the other hand, although slightly quieter than the rutted, worn roadway, was not as quiet as the original unworn road surface. Experimental Procedures The primary contribution of a road surface to the noise 'radiating from a vehicle is in the noise emitted at the road/tire interface; therefore, the major thrust of this effort was directed toward measuring this effect. There also were some measurements of community noise levels before and after the resurfacing of the bridges. The tire noise tests were taken on the right rear wheel of a Laboratory station wagon upon which a new tire was mounted (a Pennsylvania Patrol Special, size 8. 55-15). (The tread design and depth of this tire are shown on page 2. ) This tire was mounted on a wheel and used on the vehicle only daring tests. Between tests it was stored so that unnecessary wear would not change its acoustic character-teristics. The noise pickup device was a specially baffled microphone located about 7 inches from the road/tire interface by a bracket holding it on the outside of the tire. One of the major problems in making noise measurements of this type is to have a microphone that will pick up only tire noise and be baffled from wind noise. This problem has been solved by a microphone baffling system especially designed by this Laboratory.

Authors:
Foss,Rene N.

Keywords:
asphalt, bridge, bridges, community noise, design, Epoxy, experimental, floating bridge, highway, ITS, materials, mixture, noise, Noise Levels, noise measurements, performance, repair, roadway, seattle, Study, System, tests, tire, tire noise, Washington, wind, Wind Noise

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