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NEWS (Previous News Items)

  • 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.
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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.