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NEWS (Previous News Items)

  • 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.
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Spring 2016 UCPRC Activities


Candidate for fully permeable shoulder retrofit validation site

Construction of BCOA Sections at the UPCRC ATIRC Facility. Between February 23 and 25, the Concrete Pavement Industry constructed fifteen Bonded Concrete Overlay of Asphalt Pavements (BCOA) sections at the UCPRC’s Davis testing facility. The results obtained by testing on these “thin BCOA” sections will serve as the basis for recommendations and guidance on the technology’s use as a rehabilitation alternative in California, as directed by Caltrans/UCPRC Element 4.58B.

This set of sections includes a variety BCOA solutions, including several concrete mixes (type II/V, type III, and calcium sulfoaluminate cements), slab thicknesses (4.5 and 6 in.), slab dimensions (6x6 sq. ft, 6x6 sq. ft. with widened lane, and 12x12 sq. ft), asphalt base types (conventional hot mix asphalt and rubberized asphalt), asphalt base thicknesses (2 to 5 in.), asphalt conditions (old and new), and surface preparation techniques (sweeping, micromilling, and milling). All the sections were built with high early strength mixes designed to provide 400 psi flexural strength in either 4 or 10 hours, time constraints required for the short construction windows imposed by high traffic volumes and user demand on most of the main roads in the Caltrans network.

A total of 560 sensors embedded in the sections will measure displacement, strain, temperature, moisture, and relative humidity. The instruments collecting data on the concrete-asphalt interface have received especial consideration since this area’s behavior is regarded as one of the main factors determining how this rehabilitation technique will perform. Among the sensors, 245 have already been monitoring the effects of temperature and moisture-related shrinkage since construction; the rest will monitor the dynamic response of the sections under heavy vehicle simulator (HVS) loads once the one-year-long accelerated test period begins in May 2016. Laboratory testing, which is focused on the mechanical characterization of asphalt, concrete, and the interface between this two, has already started.

Expected outcomes from this research project are optimized concrete and rubberized asphalt mix designs for use as overlays and bases, respectively, for BCOA rehabilitations in California. An improved understanding of BCOA mechanics and performance is also expected from the project, which will end in September 2017.

To date, a large number of institutions have been involved in this research. These include the University of Pittsburgh, which is providing technical leadership and support, and the Southwest Concrete Pavement Association, which is coordinating Industry support that included the construction of the BCOA sections.

Important Note for Caltrans Users: Prior to scheduling pavement preservation (preventive maintenance or CAPM) or roadway rehabilitation work on flexible pavement highway sections, the District Materials Engineer and/or the Project Manager should review this spreadsheet to ensure that the proposed project does not include sections active in the “Quieter Pavement Research” (QPR) testing program. If the proposed project is within a QPR test section, please contact Linus Motumah of the Caltrans Office of Pavement Design before scheduling the work.

To view maps that show where the sections are located, click the following link: (or copy-and-paste it into a new browser window for a slightly larger view).

For more information, contact John Harvey of the UCPRC or Linus Motumah.