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NEWS (Previous News Items)

  • 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.
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Summer 2018 UCPRC Activities

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Candidate for fully permeable shoulder retrofit validation site

Life Cycle Assessment (LCA) Framework for Airfields. For many years, the Federal Aviation Administration (FAA) has taken measures to improve safety, enhance efficiency, reduce cost, and improve the sustainability of the infrastructure of US airfields, including the use of life-cycle cost analysis (LCCA) to quantify and reduce the economic cost of expanding and preserving the airfield system. However, efforts to address sustainability are incomplete if the efficiency of finite resource use—such as energy use—and environmental impacts—such as air, water, and land pollution—are not considered. Life cycle assessment (LCA) is an approach that can identify and quantify the life cycle resource use and environmental impacts of an infrastructure system such as an airfield.

The UCPRC has developed Guidelines for Life-Cycle Assessment of Airfield Pavements and Other Airside Features, a document that can support the FAA’s capacity to consider environmental impacts in decision making. The guidelines include recommendations for all phases of LCA, including goal and scope definition, life cycle inventory development, impact assessment, interpretation, critical review, and reporting. It is expected that these guidelines will be updated as experience is gained from airfield LCA studies.

The use of the LCA guidelines and framework has been demonstrated using four case studies with the help of O’Hare International Airport (Chicago), Logan International Airport (Boston), Nashville International Airport, and J. F. Kennedy International Airport (New York). The study was funded by FAA and the project report is currently under FAA review.