PREVIOUS NEWS ITEMS

  • New Tech Memo Published: Life Cycle Assessment and Life Cycle Cost Analysis for Six Strategies for GHG Reduction in Caltrans Operations. “California state government has established a series of mandated targets for reducing the greenhouse gas (GHG) emissions that contribute to climate change. With a multiplicity of emissions sources and economic sectors, it is clear that no single change the state can make will enable it to achieve the ambitious goals set by executive orders and legislation. Instead, many actors within the state’s economy–including state agencies such as the California Department of Transportation (Caltrans)–must make multiple changes to their own internal operations. The focus of this study and technical memorandum is to examine several strategic options that Caltrans could adopt to lower its GHG emissions...”
    Posted 10/8/2020.
  • New Research Report Published: Development of Performance-Based Specifications for Asphalt Rubber Binder: Interim Report on Phase 1 and Phase 2 Testing. “In the United States, the Superpave Asphalt Binder Performance Grading (PG) system proposed by the Strategic Highway Research Program (SHRP) is the most common method used to characterize the performance-related properties of unmodified and polymer-modified asphalt binders. Dynamic shear modulus (G*) and phase angle (δ) are the two main binder properties and they are measured using a dynamic shear rheometer (DSR) with parallel plate geometry and either a 1-mm or 2-mm gap between the plates. Since these Superpave parameters were developed for binders that do not contain additives or particulates, the California Department of Transportation (Caltrans) does not use them for asphalt rubber binder specifications. Instead, penetration...”
    Posted 10/8/2020.
  • New Research Report Published: Optimizing Rubberized Open-graded Friction Course (RHMA-O) Mix Designs for Water Quality Benefits: Phase I: Literature Review. “Historically, rubberized and non-rubberized open-graded friction courses (OGFCs) have been placed to provide three benefits: to increase traffic safety, to reduce urban highway noise, and to preserve the surface of the main pavement structural section. However, stringent environmental regulations on stormwater runoff management enacted recently have forced transportation agencies with limited right of ways in urban areas to search for creative methods to treat runoff and receive credits for preventing pollution from highways. This literature review was undertaken to explore ways to optimize current RHMA-O mix designs...”
    Posted 9/16/2020.
  • Caltrans/UCPRC Asphalt PRS Road Map: Performance Related Specifications for Asphalt Superpave and QC/QA. The Caltrans/UCPRC road map for development of performance related specifications (PRS) for asphalt pavement materials, integrated with mechanistic-empirical (ME) design and balanced mix design, was discussed at the Federal Highway Administration stakeholder workshop (August 11-13, 2020) on this subject. Stakeholders at the workshop were FHWA, state DOTs, the asphalt pavement industry, and university researchers.
    Posted 8/13/2020.
  • Upcoming Symposium, January 12-15, 2021: International Symposium on Pavement, Roadway, and Bridge Life Cycle Assessment 2020. Due to the current pandemic COVID-19, the International Symposium on Pavement, Roadway, and Bridge Life Cycle Assessment 2020, has been rescheduled to January 13-15, 2021, and will now be held in Davis, CA. The symposium will cover such areas as recent advances in quantifying environmental impacts using LCA for pavement, roadways, and bridges; current status and future developments; and standardization and implementation of pavement, roadway, and bridge LCA. Registration is Now OPEN.
    Posted 12/13/2019; Updated 1/4/2021.
  • New White Paper Published: Alternative Strategies for Reducing Greenhouse Gas Emissions: A Life Cycle Approach using a Supply Curve. The purpose of this white paper is to provide Caltrans with a methodology that uses life cycle assessment and life cycle cost analyses to create a “supply curve” that ranks different strategies and actions the agency can take to reduce greenhouse gas emissions and lessen the detrimental environmental impacts to ecosystems and human health. Before Caltrans can implement this proposed methodology, it must be validated and assessed using several alternative strategies that Caltrans is considering or might consider. The strategies evaluated were selected by the authors based on information available to them, and do not necessarily reflect Caltrans policies or priorities. This white paper presents the methodology and demonstrates its initial use in quantifying and ranking several potential strategies.
    Posted 8/12/2020.
  • New Research Report Published: Development of Improved Guidelines and Designs for Thin Whitetopping: Environmental Response of Full-Scale BCOA Sections. “Fifteen bonded concrete overlay of asphalt (BCOA) sections were built at the UCPRC facility in Davis, California, from February 23 to 25, 2016. The concrete mixes included Type II/V and Type III portland cements and calcium sulfoaluminate cement, and they were designed to provide 2.8 MPa (400 psi) flexural strength after either 4 or 10 hours. Six of the 15 sections were instrumented with a total of 245 sensors to measure the responses to environmental actions and cement hydration. Based on the analysis of the data collected by these sensors up until May 31, 2017, preliminary conclusions were drawn regarding how the different section configurations and concrete types responded to moisture and temperature-related actions. A clear link between drying shrinkage, concrete relative humidity, and environmental conditions was verified. Very high levels of drying shrinkage were measured...”
    Posted 5/18/2020.
  • New Tech Memo Published: Development of Thin Bonded Concrete Overlay of Asphalt Design Method: Evaluation of Existing Mechanistic-Empirical Design Methods. “The California Department of Transportation (Caltrans) is interested in advancing the technology needed to implement thin bonded concrete overlay of asphalt (BCOA) on its road network. Recent accelerated pavement tests showed that thin BCOA exhibited promising results for structural performance and constructability in California’s dry environment when made with the high early-strength concrete mixes typically used by Caltrans. However, to continue moving forward, Caltrans needs to adopt a thin BCOA design method since the current Caltrans Highway Design Manual does not consider this type of pavement. In order to help Caltrans decide how to adopt a thin...”
    Posted 4/24/2020.
  • Presentation: Alameda County Green Procurement Roundtable-December 10, 2019. John Harvey made a presentation to the Alameda County Green Procurement Roundtable in Hayward on 10 December, 2019 to an audience of city and county pavement engineers, sustainability officers, and procurement officers. The presentation covered methods to quantify environmental impacts, and recommendations for how local government can reduce the impacts of their pavement operations and decisions.
    Posted 12/13/2019.
  • New Research Report Published: Development of Improved Guidelines and Designs for Thin BCOA: Summary, Conclusions, and Recommendations. This report summarizes the investigations undertaken by the UCPRC between 2014 and 2017 to develop recommendations and guidance on the use of thin bonded concrete overlay of asphalt (BCOA) as a rehabilitation alternative for California based on the adoption of, and improvements to, the technology developed in other US states. The report summarizes, among other things, the Heavy Vehicle Simulator testing of eleven thin BCOA sections. The main conclusion from this research project is that a well-designed, well-built 6×6 thin bonded concrete overlay placed on top of an asphalt base that is in fair-to-good condition can potentially provide 20 years of good serviceability on most of California’s non-interstate roadways.
    Posted 8/19/2019.
  • Presentation Given: John Harvey made a keynote presentation in the Sustainability and Circular Economy session of the European Asphalt Technology Association (EATA) 8th Conference at the University of Granada, Spain on 3 June, 2019.
    Posted 6/4/2019.
  • Call for Abstracts: The International Symposium on Pavement, Roadway, and Bridge Life Cycle Assessment 2020, to be held in Sacramento, California on June 3-6, 2020 is now accepting abstracts. Abstracts should be submitted by June 15, 2019. To submit abstracts, you need to set up an account with EasyChair. Go to https://easychair.org/conferences/?conf=lca2020 and click “create an account”. The LCA2020 Instructions for Authors document details the process of creating an EasyChair account and submitting an abstract. You only need to specify the first author at submission time (you can specify all authors if you would like) andyou can add additional authors (or remove and/or update authors) later by logging into EasyChair andupdating your submission.
    Posted 3/12/2019.
  • New Research Report Published: Laboratory Evaluation of the Mechanical Properties of Asphalt Concrete Reinforced with Aramid Synthetic Fibers. “The research project presented in this report evaluates the effects that the addition of aramid fibers has on the mechanical properties of a dense-graded mix frequently used in California, a Superpave mix with 19 mm (3/4 in.) nominal maximum aggregate size, 15 percent reclaimed asphalt pavement (RAP) content, and PG 64-10 binder. A fiber-reinforced asphalt concrete (FRAC) was prepared by adding aramid fibers at a rate of 0.013 percent of total mix weight. The mechanical properties of the two mixes, original and FRAC, were determined in the laboratory. Based on laboratory testing, adding the fibers improved fatigue resistance...”
    Posted 4/29/2019.
  • New Research Report Published: Pavement Recycling: Shrinkage Crack Mitigation in Cement-Treated Pavement Layers - Phase 1 Laboratory Testing. “The California Department of Transportation (Caltrans) has been using full-depth reclamation (FDR) as a rehabilitation strategy since 2001. Most projects to date have used a combination of foamed asphalt and portland cement as the stabilizing agent. Recently though, the fluctuating and at times high cost of asphalt binder coupled with the relatively complex mix-design procedure for mixes that include foamed asphalt has generated interest in the use of portland cement alone as an alternative stabilizing agent. However, shrinkage cracking associated with the hydration and curing...”
    Posted 12/10/2018.
  • New Research Report Published: Guidance for Selection of Unbound Pavement Layer Seasonal Stiffnesses. “One of the benefits of using mechanistic-empirical (ME) design methods for pavements is the ability to calculate pavement response to various loading and climate conditions, and then in turn to model the entire damage process that is expected to occur over the pavement lifetime. One property that is currently not accounted for within California’s ME design software (CalME) is the change in stiffness of unbound materials that may occur due to seasonal moisture patterns. The engineering properties of unbound material may change due to a variety of factors, such as fluctuations in water content, changes in suction during wetting or drying periods, changes in overburden stress, and they are also dependent on geologic setting. Before moving to develop and implement more complex relationships to model assumed changes in the properties of unbound layers due to seasonal moisture changes...”
    Posted 11/20/2018.
  • New Research Report Published: Mechanistic-Empirical (ME) Design: Mix Design Guidance for Use with Asphalt Concrete Performance-Related Specifications. “Caltrans has adopted mechanistic-empirical (ME) methods for flexible pavement design, and is using performance-related construction specifications on some projects for hot mix asphalt. Performance-related specifications are used to help ensure that as-built materials meet the performance requirements assumed in ME pavement structural designs. PRS pose new challenges for materials producers and contractors who have never had to relate volumetric mix design parameters to achievement of mechanistic parameters for fatigue life and rutting resistance based on results from performance-related laboratory tests. The objective of this project is to provide guidance to mix designers and contractors to support their decision making regarding changes to mix designs to achieve PRS requirements. The guidance presented in this report was initially developed based on past experience. To validate...”
    Posted 8/24/2018.
  • New Research Report Published: Development of Improved Guidelines and Designs for Thin Whitetopping: Design, Instrumentation, Construction and Initial Environmental Response of Full-Scale BCOA Sections. “Thin bonded concrete overlay of asphalt (BCOA) is a rehabilitation alternative consisting of a 100 to 175 mm (0.33 to 0.58 ft) thick portland cement concrete (PCC) overlay of an existing flexible or composite pavement. Fifteen BCOA sections were built at the Davis facilities of the University of California Pavement Research Center in February 2016. Eleven of these full-scale sections were tested under accelerated loading, while four of them were used for monitoring the response of BCOA to the ambient environment and cement hydration. This full-scale experiment is part of a research project whose primary goal is to develop recommendations and guidance on the use of thin BCOA as a rehabilitation alternative in California. The design and construction of these sections is presented in this report, together with results from the quality control/quality assurance testing that was conducted. This testing...”
    Posted 8/20/2018.
  • New Research Report Published: Final Report: Permeable Pavement Road Map Workshop and Proposed Road Map for Permeable Pavement. “In early 2017, the University of California Pavement Research Center (UCPRC) and the National Center for Sustainable Transportation (NCST), working with the Interlocking Concrete Pavement Institute (ICPI), identified gaps in knowledge and other barriers to wider implementation that were perceived to be holding back the full potential for deployment of pavements that can simultaneously solve transportation, stormwater quality, and flood control problems. Further discussions were held with the National Ready Mixed Concrete Association (NRMCA), the National Asphalt Pavement Association (NAPA), and the Tongji University Sponge City Project (Shanghai, China). A workshop was organized in November 2017 based on those discussions with the goal of identifying...”
    Posted 8/16/2018.
  • New Tech Memo Published: Effects of Milling and Other Repairs on Smoothness of Overlays: Additional Testing on Construction Under Profiler-Based Smoothness Specifications. “This technical memorandum provides additional information regarding smoothness on several thin asphalt overlay projects constructed soon after changes in Caltrans specifications for constructed pavement surfaces using the International Roughness Index (IRI) as the quality metric. The IRI data were collecting using inertial profilers, before and after construction, on overlaid surfaces employing one of three repairs—digouts, cold in-place recycling (CIR), mill and filling—or none. Because the data were collected after the close of the construction contract, they include the effects of any grinding that Caltrans...”
    Posted 7/17/2018.
  • Two Presentations Given: A presentation on Reducing Pavement Life Cycle Impacts Using LCA was made by UCPRC at the California Asphalt Pavement Association (CalAPA) Conference and Equipment Expo on April 25, 2018. A keynote presentation on Asphalt Pavement Life Cycle Assessment: Review and Future Outlook was given by John Harvey in Harbin, China for the International Symposium on Road Development on May 5, 2018.
    Posted 6/15/2018.
  • New Tech Memo Published: Development of the CalME Standard Materials Library. “The main purpose of the project is to improve the ability of Caltrans pavement designers to use mechanistic-empirical (ME) pavement design procedures that were developed and calibrated for California conditions as part of Partnered Pavement Research Center Strategic Plan Element (PPRC SPE) 4.1 and refined in SPE 3.4. Specifically this project is part of a long-term series of tasks to collect regional materials data for use by Caltrans in ME flexible pavement designs and rehabilitations. This technical memorandum documents ...”
    Posted 4/19/2018.
  • New Tech Memo Published: Permeability Testing on Dense-Graded Hot Mix Asphalt (HMA) and Gap-Graded Rubberized Hot Mix Asphalt (RHMA-G) Surfaces. “Falling head permeability tests were conducted on seven projects, four with dense-graded hot mix asphalt surfaces and three with gap-graded rubberized hot mix asphalt surfaces. Tests were conducted between the two wheelpaths and in the right wheelpath, and in both directions of traffic. Averaging all the test results shows that ...”
    Posted 3/26/2018.
  • New Guideline Published: Guidelines for the Selection, Specification and Application of Chemical Dust Control and Stabilization Treatments on Unpaved Roads. This guide introduces a new process for selecting an appropriate chemical treatment category for a specific set of unpaved road conditions using ranked potential performance. The process is based on a practitioner’s setting an objective for initiating a chemical treatment program and then gaining a fuller understanding of the road in terms of materials, traffic, climate, and geometry. Using the information collected, the most appropriate chemical treatment subcategories for a given situation can be selected from a series of charts and ranked using a simple equation. This process can be completed manually using a paper form, or by using a web-based tool. Matrices for each of the objectives were developed based on documented field experiments and the experience of a panel of practitioners. Guidance on specification language for procuring and applying unpaved road chemical treatments is also provided, along with comprehensive guidance on understanding unpaved road wearing course material performance.
    Posted 3/20/2018.
  • The Beguiling Science of Making Planet-Saving Pavement: Changing how we make the pavements we walk and drive on could make a real dent in California’s greenhouse gas emissions output, according to a Wired magazine article that cites UCPRC and its lifecycle studies. UC Davis Civil & Environmental Engineering Professors Alissa Kendall and John Harvey, Director of UCPRC, are both quoted: https://www.wired.com/story/pavement-environment-science.
    Posted 2/5/2018.
  • New Tech Memo Published: Performance Based Specifications: Literature Review on Increasing Crumb Rubber Usage by Adding Small Amounts of Crumb Rubber Modifier in Hot Mix Asphalt. “A comprehensive review of the literature covering more than 100 published journal articles, conference proceedings, and reports found that although considerable research has been undertaken to understand the advantages and disadvantages of using recycled tire rubber to modify asphalt binders, no published information on PG+X-type initiatives (i.e., focused more on using additional waste tires in asphalt mixes rather than on improving performance of the binder and mix) was found. A number of states ...”
    Posted 1/25/2018.
  • New Report Published: Support for Superpave Implementation: Round Robin Hamburg Wheel-Track Testing. “A round robin testing program was undertaken between 20 participating laboratories in California to assess the reproducibility of Hamburg Wheel-Track (HWT) test results as part of a Superpave implementation initiative. Each laboratory conducted four HWT tests. Two of the tests were conducted on gyratory-compacted specimens prepared by the University of California Pavement Research Center (UCPRC), and the other two were conducted on gyratory-compacted specimens prepared by ...”
    Posted 12/22/2017.
  • Advances in Highway and Airfield Pavement Research. In August 2017, UCPRC staff attending the ASCE International Conference on Highway Pavements & Airfield Technology in Philadelphia delivered eight presentations on a variety of highway and airfield topics, as well as a short course on environmental product declarations (EPD). The four conference themes focused the discussions of the more than 300 national and international experts from academia and industry on design and construction, materials, airfield and safety, and innovations and sustainability. A variety of presentations addressed the current and critical challenges affecting airfield and highway performance, pavement sustainability, and airfield safety. More information about the conference can be found at www.pavementsconference.org.
    Posted 9/19/2017.
  • A Vision for the Future of the Pavement Enterprise. John Harvey, professor in Civil and Environmental Engineering and Director of the UC Pavement Research Center (UCPRC) presented the Rasmus S. Nordal keynote address to more than 400 delegates at the 10th Conference on the Bearing Capacity of Roads, Railways and Airfields in Athens, Greece, on June 28, 2017. Titled “Imposed vs. Chosen Change: A vision for the Future of the Pavement Enterprise,” the lecture looked at whether “stationarity”—the idea that the needs of future design can be based on past needs—applies to the future of pavement. The lecture reviewed expected changes in the demand for pavement for personal mobility and freight, the effects of projected vehicle technology changes on pavement, increased expectations and functional requirements that pavements will need to meet, and recommended changes in the academic and government sectors of the pavement enterprise to meet future demands and expectations. The presentation is downloadable here.
    Posted 7/7/2017.
  • Local Government Pavement Research. Local governments bear responsibility for 80% of the roadway pavement lane-miles in California, which carry 45% of the vehicle miles traveled. However, these governments face a growing backlog of projects, and need new approaches to reduce the costs of preservation, maintenance, rehabilitation and reconstruction. They also need help improving their staff’s knowledge of the most cost-efficient and lowest environmental impact approaches to those tasks, and they need it delivered in ways that meet their needs. Currently, California does not have a well-organized systematic approach for delivering this technical content to local governments, but several other states do. The UCPRC recently helped complete a white paper that canvased other states to develop a summary of best practices and gaps in other states’ approaches for delivering technical pavement management content to local governments, and recommends an approach for California. The white paper is downloadable here. Posted 5/31/2017.
  • Pavement Life-Cycle Assessment Symposium. In April, the Pavement Life-Cycle Assessment Symposium 2017 at the University of Illinois at Urbana-Champaign brought together more than 130 national and international experts from academia and industry, including researchers from the UCPRC. Discussions focused on implementing LCA for pavements globally, the current state of LCA implementation at project- and network levels, development of programs for Environmental Product Declarations, future plans and needs for pavement LCA, and more. Information and presentations are available at http://lcasymposium.ict.illinois.edu/program/. Posted 5/31/2017.
  • EPD Workshop Report. An FHWA-sponsored workshop on Environmental Product Declarations was held September 13-15, 2016, at the Michigan Technical University research offices in Ann Arbor, Michigan. The goal of the workshop was to assess the prospects and obstacles for production of Environmental Product Declarations (EPD) by industry, and their use by public and private owners. The workshop included gatherings that focused on three primary concerns. The first was the global benchmarking of the ability of industry to produce EPDs and of owners to use EPDs. The second sought to identify the institutional barriers, technical gaps, human resource and level-of-expertise capacity limitations, and cost constraints holding back the development of uniform standards and approaches to collecting, organizing, and documenting data inventories that are in keeping with the data quality standards outlined in ISO 14025, and implementation of ISO 14025 in the European EN 15804 standard, and recently published FHWA Pavement LCA guidelines. Third, participants worked to create a vision for the future production and use of EPDs that includes solutions for standardization, strategies for overcoming barriers and gaps, and ideas for constraining costs. In plenary presentations, workshop participants framed the issues and posed questions that were addressed in workshops that followed (and where further questions were sometimes raised). Final day discussions focused on developing the outline of a draft road map for a way forward. The report from the workshop is available here. Posted 2/28/2017.
  • Bicycle Ride Quality Study. To identify pavement treatment surfaces that are more acceptable to California’s increasing number of bicyclists as well as safe for motorists, the UCPRC undertook and recently completed the second part of a Caltrans-sponsored study into roughness and surface textures that could satisfy both sets of road users. A report on the study is now available. It contains a set of recommended guidelines that can be used to select pavement surface treatments for both urban and rural roads that maximize bicycle ride quality based on surface texture, combined with the effects of road roughness. This multi-faceted study built on the earlier study by including a wider range of bicycle types and riders, and considering urban preservation treatments and city streets as well as treatments used on state highways and county roads. The recommendations in the study are based on user surveys as well as investigation of the effects of preservation treatment aggregate gradations on surface texture and the mechanistic responses of bicycles to pavement macrotexture and roughness. Posted 2/13/2017.
  • HMA Performance-Based Specifications Tech Memos. Three new technical memos are now available that document Caltrans-sponsored UCPRC research on projects whose aim is the development of HMA performance-based specifications for long-life pavements. The memos provide the study’s results and describe how Caltrans and the UCPRC collaborated to finalize the mix designs, perform laboratory mix testing, and establish performance criteria for two long-life pavement projects in Caltrans District 2 (one north of the city of Red Bluff and another north of the city of Weed) and one in District 4 (on Interstate 80 in Solano County). Caltrans put the resulting data to use by making it available to contractors bidding to construct the projects and by having its staff pavement designers use it with CalME flexible pavement design methodology. Now that the projects are in place, Caltrans has continued the follow up performance monitoring included in the memos’ recommendations. Posted 11/8/2016.
  • Throughout the summer, the UCPRC has continued sampling pavement materials from asphalt plants around California to gather data for the Standard Materials Library in development for Caltrans and for use in the pavement design software CalME. This sampling work and the research that will build on it have been enabled by industry partners, whose facilities include equipment like the new asphalt sampler and splitter in use at plants in Orland and San Diego. This device minimizes the impact of sampling asphalt materials during production. Posted 7/19/2016.
  • Pavement structural response, macrotexture, and roughness all affect vehicle fuel consumption, but how great the effect of structural response is has not been fully examined yet. A new UCPRC report provides insights based on calculations made with data from measurements on 17 asphalt-surfaced California pavements, including flexible, composite and semi-rigid structures. Three types of models were use to simulate annual excess fuel consumption due to structural response (EFCS) for a factorial of vehicles, traffics flows, speed distributions, and climate regions, and these results were compared with increased fuel consumption caused by roughness and macrotexture. Initial recommendations from the study include adding models for concrete pavements, considering multiple layers in the asphalt, and checking the effects of full dynamic pavement modeling. The next step in the project is field calibration of the models. Posted 6/1/2016.
  • The UCPRC made podium and poster presentations at the 2016 Transportation Research Board (TRB) Annual Meeting held in Washington, DC on January 10-14, 2016. The presentations covered work sponsored primarily by the California Department of Transportation (Caltrans) as well as CalRecycle and the FHWA. Posted 2/8/2016.
  • The work being done by the UCPRC for Caltrans and others was presented at the Australian Asphalt Pavement Association Annual Conference from September 14-16, 2015. Presentations were made on CalME mechanistic-empricial design, development of mechanistic-empirical design methods, heavy duty asphalt pavement design, and a keynote address on driving innovation in pavements. Posted 10/19/2015.
  • A summary of the research findings and design procedure developed during the recently completed permeable interlocking concrete pavement study (see Summer 2015 UCPRC Activities below) was presented at the 11th International Conference on Concrete Block Pavement in Dresden, Germany in September. The design tables developed with the design procedure have been incorporated into the Interlocking Concrete Pavement Institute and ASTM guidelines for designing and constructing permeable interlocking concrete pavements. Posted 10/13/2015.
  • The Caltrans/UCPRC Heavy Vehicle Simulators have completed all testing of different full-depth pavement reclamation strategies on one of the instrumented test tracks at the UC Davis research facility. The strategies included pulverization with no stabilizer (FDR-NS), pulverization with cement (FDR-PC), pulverization with foamed asphalt/cement (FDR-FA), and pulverization with engineered emulsion (FDR-EE). Testing was done under both dry and soaked conditions, with a total of 8.5 million wheel load repetitions applied with the HVSs, equating to about 145 million equivalent single axle loads (ESALs) . A comprehensive forensic investigation has also been completed on each test section. Posted 10/13/2015.
  • The UCPRC has recently worked with colleagues in China and South Africa to expand knowledge of pavement life cycle assessment and support development of national programs for considering development and implementation of pavement LCA. A two day workshop (August 7-8) organized by Jia Yu of the Jiangsu Transportation Institute Group Company, Ltd. and Tan Yiqiu of the Harbin Institute of Technology, who also hosted the event, drew participants from across a wide range of stakeholders in China. Keynote presentations given by UCPRC are available here. In South Africa, the UCPRC participated in the 3rd ISAP International Symposium on Asphalt Pavements and the Environment which focused on improving the sustainability of pavements and was part of the 11th Conference on Asphalt Pavements in Southern Africa. The keynote presentation given by UCPRC on pavement LCA is available here. A workshop was held with industry, government and academic participants to discuss pavement LCA for application in southern Africa, and a resolution has been prepared from the workshop for review by government and industry in South Africa. Posted 8/25/2015.
  • A presentation by UCPRC researchers at the 52nd Petersen Asphalt Research Conference (July 13 to 15, 2015, in Laramie, Wyoming) described the progress of, and some recent findings from, three current studies: 1) Modification of the rolling thin-film oven (RTFO) test to simulate the realistic short-term aging of asphalt rubber binders (view presentation); 2) An evaluation of changes in the performance-related properties of conventional asphalt binder after it is blended with different amounts of age-hardened rubberized binder (view presentation); and 3) Development of a solvent-free approach for evaluating the properties of blended binders in mixes that have large reclaimed asphalt pavement (RAP) and reclaimed asphalt shingle (RAS) content (view presentation). Posted 8/7/2015.
  • The Caltrans/UCPRC Heavy Vehicle Simulators are currently testing different full-depth pavement reclamation strategies on one of the instrumented test tracks at the UC Davis research facility. The strategies include pulverization with no stabilizer (FDR-NS), pulverization with cement (FDR-PC), pulverization with foamed asphalt/cement (FDR-FA), and pulverization with engineered emulsion (FDR-EE). All testing under dry and soaked conditions has been completed. The final test to evaluate the effect of high surface temperatures on rutting in foamed asphalt treated bases is currently in progress. Forensic testing on completed test sections is in progress. HVS testing on this project is scheduled to end at the end of August 2015 and forensic investigations will be completed in September 2015. Posted 8/7/2015.
  • The UCPRC will be sampling and testing throughout California on state highways and on a few construction projects. The objective is to build up the material library for use with Caltrans' mechanistic empirical design method (CalME). We are evaluating the in-situ stiffness of various materials, including cement treated base, lean concrete base, cold in place recycled material, and full depth recycled materials with or without stabilizing agents. Several rounds of testing will be conducted to capture the effects of seasonal variation, curing/aging, and trafficking on layer stiffness. Please remember to drive slow for the cone zone, and move away a lane if possible. We appreciate it. Posted 6/15/2015.
  • In April, the Caltrans/UCPRC-operated Inertial Profiler Certification Center completed its second 2015 session of operator and profiler exams. These sessions are conducted as part of an effort to support Caltrans' implementation of IRI-based smoothness specifications in the state. Coordinating its efforts with Caltrans at the Sacramento certification site, the UCPRC certified 22 operators and 11 profiler vehicles, the largest number of each certified in any session to date. More information about this program and its services are available here, including details on the next scheduled certification date in June 2015. Posted 6/15/2015.
  • The Caltrans/UCPRC Heavy Vehicle Simulators are currently testing different full-depth pavement reclamation strategies on one of the instrumented test tracks at the UC Davis research facility. The strategies include pulverization with no stabilizer (FDR-NS), pulverization with cement (FDR-PC), pulverization with foamed asphalt/cement (FDR-FA), and pulverization with engineered emulsion (FDR-EE). Testing is currently taking place under soaked conditions on the FDR-NS test section with 120mm asphalt surfacing and under high pavement temperatures in dry condition on the FDR-FA test section. HVS testing on this project is scheduled to end at the end of June 2015. Posted 5/18/2015.
  • A presentation was made at the California Asphalt Pavement Association (CalAPA) conference in Ontario on April 16th by John Harvey. The presentation included a look at the 2000 pavement research vision document and a review of progress towards its 15 year goals, a look at ahead at some expected major future research challenges, an overview of the current Caltrans/UCPRC Pavement Research Roadmap projects related to asphalt pavement, and a summary of the Asphalt Concrete Long Life (AC Long Life) long-life rehabilitation strategy that Caltrans District 8 is contemplating using on an upcoming segment of damaged freeway. Posted 4/21/2015.
  • The Caltrans/UCPRC Heavy Vehicle Simulators are currently testing different full-depth pavement reclamation strategies on one of the instrumented test tracks at the UC Davis research facility. The strategies include pulverization with no stabilizer (FDR-NS), pulverization with cement (FDR-PC), pulverization with foamed asphalt/cement (FDR-FA), and pulverization with engineered emulsion (FDR-EE). Testing is currently taking place under soaked conditions on the FDR-FA and FDR-PC test sections. Current load repetition count on the FDR-FA is 700,000 at an 80kN half axle load (36,000lb single axle load) and 300,000 on the FDR-PC at a 40kN (18,000lb) load. Posted 3/16/2015.
  • The LCA 2014 web page with documentation of the Pavement LCA 2014 Symposium has been created and is now LIVE! It includes the program, presentations, papers, results of the breakout sessions, and information about attendees and committees. Follow up meetings on Pavement LCA are being planned for Harbin, China (contact Hui Li for information) and Sun City, South Africa (just before CAPSA, organized by ISAP APE) in August, 2015. Posted 2/6/2015.
  • The UCPRC made podium and poster presentations at the 2015 Transportation Research Board (TRB) Annual Meeting held in Washington, DC on January 11-15, 2015. The presentations covered work sponsored primarily by the California Department of Transportation (Caltrans) as well as the California Air Resources Board (CARB). Posted 1/29/2015.
  • In January 2015, the UCPRC published the fourth and final report based on the Freight-Truck-Pavement interaction pilot study. This logistics augmentation aspect of the study was conducted to examine the ways that public and private sector decision makers approach issues related to road-freight transport in California and to show how direct consultation between the two sectors might align their interests more closely. This project included desktop studies, qualitative analysis, and case studies. Among its other findings, the study concluded that road infrastructure and regulation have a marked impact on the state’s critical supply chain operations and strategies, and that the state may benefit when Caltrans and the private sector engage in the planning and construction of road infrastructure as well in the drafting and implementation of policy. Posted 1/26/2015.
  • Just published on the UCPRC website are the results from the final tasks (Tasks 9 to 11) of a three-phase pilot study (Tasks 1 to 6 and Tasks 7 and 8) undertaken for Caltrans demonstrating the potential economic and other effects of changes in vehicle-pavement interaction caused by varying surface roughness, which can increase from road maintenance delays and pavement management decisions. Undertaken in collaboration with the University of Pretoria and the Council for Scientific and Industrial Research (CSIR) in South Africa, the study used state-of-the-art tools to simulate and measure the peak loads and vertical acceleration of trucks and their freight on a selected range of pavement surface profiles on the state highway system. The study’s aim is to enable Caltrans to better manage the risks of decisions regarding freight and the management and preservation of the pavement network by quantifying the results in economic terms and other effects. Posted 12/16/2014.
  • In September 2014, the UCPRC published the report “Improved Methodology for Mix Design of Open-Graded Friction Courses”. This study presents an improved methodology for the mix designs of open-graded friction courses (OGFC). The methodology has been enhanced by the development of an Excel macro in order to suggest revisions to California Test 368, Standard Method for Determining Optimum Binder Content (OBC) for Open-Graded Asphalt Concrete. In addition to the development of the Excel macro, one of the primary objectives of this study was to evaluate the effect that fines content has on mix performance, which cannot be identified by the “break point sieve” concept or by volumetric properties. Posted 9/30/2014.
  • The Inertial Profiler Certification Program is up and running. Six certifications have been performed since July 2013. The program, which is intended to ensure that qualified operators and profilers perform pavement QA testing, has certified 25 operators and 18 inertial profilers to date. Follow the links to see the lists of Certified Operators and Profilers. Posted 7/22/2014.
  • The variability of On-board Sound Intensity (OBSI) testing results due to different equipment operators is an important consideration in the study of tire/pavement noise on both flexible and rigid pavements. Results of an OBSI "rodeo" conducted by the UCPRC--in partnership with Illingworth and Rodkin (Petaluma, CA)--showed that the difference among test vehicles with different operators was, at most, about 1 decibel, a finding consistent with other OBSI comparisons. Posted 9/30/2014.
  • In June 2014, the UCPRC published the report “Evaluation of Grind and Groove (Next Generation Concrete Surface) Pilot Projects in California”. This report documents a field study undertaken for Caltrans to evaluate pilot projects where this new texturing technique was applied to existing concrete pavements to see whether it would produce quieter and smoother pavement surfaces. The study’s results, based on data collected on seven pilot projects in the Central Valley and San Diego, cover tire/pavement noise, smoothness, skid resistance, and cost, and offer preliminary recommendations regarding where it is most appropriate to use this texture. Posted 7/7/2014.
  • In May 2014, the UCPRC published the report “Surface Treatment Macrotexture and Bicycle Ride Quality”, documenting the results of a study carried out for Caltrans. The report contains research results and preliminary recommendations regarding surface treatment gradations, texture, bicycle vibration, and bicyclists' perceptions of ride quality that are based on data collected on more than 40 northern and central California pavement sections and from over 100 survey participants. Posted 6/16/2014.
  • A study to assess the performance of permeable interlocking concrete pavers in pavement applications continues at the UCPRC facility at UC Davis on behalf of the Interlocking Concrete Pavement Institute Foundation for Education and Research. The first phase of testing under dry conditions was completed in early April. Water was then added and the second phase of HVS testing started to assess performance with a wet subgrade and water in the reservoir layer. Wet testing was completed at the end of May. Some additional response data under varying moisture conditions is now being collected. Posted 6/9/2014.
  • A study to assess the performance of permeable interlocking concrete pavers in pavement applications continues at the UCPRC facility at UC Davis on behalf of the Interlocking Concrete Pavement Institute Foundation for Education and Research. The first phase of testing under dry conditions was completed in early April. The test track was then flooded and the second phase of HVS testing started to assess performance under soaked conditions. Posted 4/28/2014.
  • A new study to assess the performance of permeable interlocking concrete pavers in pavement applications has recently been initiated at the UCPRC facility at UC Davis on behalf of the Interlocking Concrete Pavement Institute Foundation for Education and Research. Construction of a two-lane, 30m long test track using this technology was completed in late January 2014. HVS testing is scheduled to start on the track in early February. Posted 2/6/2014.
  • The two Caltrans/UCPRC Heavy Vehicle Simulators have completed testing of four different full-depth pavement reclamation strategies on one of the instrumented test tracks at the UC Davis pavement research facility. These strategies include pulverization with no stabilizer (FDR-NS), with cement (FDR-PC), with foamed asphalt/cement (FDR-FA), and with engineered emulsion (FDR-EE). Data analysis and preparation of the project report continues. A second round of HVS testing to assess the sections in a soaked state is currently being discussed with Caltrans. Posted 1/6/2014.
  • The two Caltrans/UCPRC Heavy Vehicle Simulators are at present testing four different full-depth pavement reclamation strategies on one of the instrumented test tracks at the UC Davis research facility. These strategies include pulverization with no stabilizer (FDR-NS), with cement (FDR-PC), with foamed asphalt/cement (FDR-FA), and with engineered emulsion (FDR-EE). Testing has been completed on the FDR-NS and FDR-FA sections and continues on the FDR-PC section (currently 1,350,000 load repetitions, testing at 100kN, equivalent to a single axle load of 45,000 lbs.) and FDR-EE section (currently 60,000 load repetitions with a test load of 40kN (equivalent to a single axle load of 18,000 lbs). Posted 10/27/2013.
  • UCPRC is participating in an FHWA round robin study evaluating the interlaboratory variability of results of AASHTO T336-11 testing of the coefficient of thermal expansion of concrete. The UCPRC finished the necessary testing and returned the results to FHWA in early September 2013. Posted 10/21/2013.
  • The UCPRC has published a technical memo for Caltrans that contains initial results and preliminary recommendations regarding surface treatment gradations, macrotexture, bicycle vibration, and bicyclists' perceptions of ride quality. The final report will be completed in several months and will include results from additional pavement test sections. Posted 10/21/2013. Add a review.
  • The two Caltrans/UCPRC Heavy Vehicle Simulators are at present testing four different full-depth pavement reclamation strategies on one of the instrumented test tracks at the UC Davis research facility. These strategies include pulverization with no stabilizer (FDR-NS), with cement (FDR-PC), with foamed asphalt/cement (FDR-FA), and with engineered emulsion (FDR-EE). Testing has been completed on the FDR-NS and FDR-FA sections and continues on the FDR-PC section (currently 900,000 load repetitions, testing at 100kN, equivalent to a single axle load of 45,000 lbs). Testing has just started on the FDR-EE test section with a test load of 40kN (equivalent to a single axle load of 18,000 lbs). Posted 10/2/2013.
  • The roll out to the districts of Caltrans' new pavement management system, called PaveM, has begun. Training for District 7 (Los Angeles) was completed in August and the next training session in District 10 (Stockton) will be held in early October 2013. Posted 9/12/2013.
  • The Caltrans/UCPRC-operated Inertial Profiler Certification Program completed its first two operator and profiler certification sessions in July and August 2013. UCPRC's work to help establish both the certification site and the program supports Caltrans' implementation of an IRI-based smoothness specification. Information about the program and its services is available here. Posted 9/12/2013.
  • The two Caltrans/UCPRC Heavy Vehicle Simulators are at present testing four different full-depth pavement reclamation strategies on one of the instrumented test tracks at the UC Davis research facility. These strategies include pulverization with no stabilizer (FDR-NS), with cement (FDR-PC), with foamed asphalt/cement (FDR-FA), and with engineered emulsion (FDR-EE). Testing is now taking place on the FDR-PC and FDR-NS test sections, with load repetition counts to date of 600,000 and 750,000, respectively. Both machines are currently trafficking at 100 kN loads, equivalent to a single axle load of 45,000 lbs. Posted 9/12/2013.
  • APT2012, the 4th International Conference on Accelerated Pavement Testing, will be held in Davis, California, in September 2012. Information and registration are available here.
  • Lifecycle Analysis Framework Kick-off Workshop held at UCPRC, May 2010. More information is available here.