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NEWS (Previous News Items)

  • 2021-22 Annual Report Released: Partnered Pavement Research Center Annual Report: Fiscal Year 2021-2022 (PDF). Highlights of work that the Caltrans/UCPRC Partnered Pavement Research Center (PPRC) started, completed, or implemented during the 2021-2022 fiscal year.
    Posted 11/29/2022.
  • 2020-21 Annual Report Released: Partnered Pavement Research Center Annual Report: Fiscal Year 2020-2021. Highlights of work that the Caltrans/UCPRC Partnered Pavement Research Center (PPRC) implemented during the 2020-2021 fiscal year.
    Posted 9/27/2021, revised 12/1/2022.
  • New Research Report Published: Updates to CalME and Calibration of Cracking Models. “The CalME flexible pavement simulation and design software program has been completely recoded as a web-based application calledCalME 3.0. CalME 3.0 retains the same incremental-recursive damage approach and the same forms for damage models and transferfunctions as CalME 2.0, which was validated using accelerated pavement testing data from Heavy Vehicle Simulator (HVS) test sectionsand the WesTrack experiment.The following enhancements and additions are all included in the revised program. First, the old software’s fatigue cracking transferfunctions for hot mix asphalt (HMA) on aggregate base, cement-stabilized bases, and portland cement concrete have been recalibratedusing a new approach for the calibration...”
    Posted 6/7/2021.
  • New Research Report Published: Pavement ME Sensitivity Analysis (Version 2.5.3). “The Mechanistic-Empirical Pavement Design Guide (MEPDG) is a comprehensive tool developed in 2002 by the American Association of State Highway and Transportation Officials (AASHTO) to analyze and design both flexible and rigid pavements. The models in the MEPDG are implemented in software called Pavement ME, a program calibrated using Long-Term Pavement Performance (LTPP) sections from throughout the United States, including some from California. The MEPDG recommends that nationally calibrated models be validated using local data, and if necessary, recalibrated, which makes sense when considering the climate and materials differences between California and the rest of the nation. The first step in recalibrating Pavement ME is to perform a sensitivity analysis to identify which variables are most important and to look for results that do not match...”
    Posted 5/28/2021.
  • New Guideline Published: Guide for Partial- and Full-Depth Pavement Recycling in California. “This document has been prepared to guide practitioners on project investigation, recycling strategy selection, pavement structural design, environmental life cycle and life cycle cost assessment, mix design, and construction of in-place pavement recycling projects on flexible pavements in California. It provides information specific to California conditions to supplement the California Highway Design Manual (HDM), specification documents, and other available...”
    Posted 2/24/2021.
  • New Research Report Published: Effects of Increased Weights of Alternative Fuel Trucks on Pavement and Bridges. “California’s truck fleet composition is shifting to include more natural gas vehicles (NGVs), electric vehicles (EVs), and fuel cell vehicles (FCVs), and it will shift more quickly to meet state greenhouse gas (GHG) emission goals. These alternative fuel trucks (AFTs) may introduce heavier axle loads, which may increase pavement damage and GHG emissions from work to maintain pavements. This project aimed to provide conceptual-level estimates of the effects of vehicle fleet changes on road and bridge infrastructure. Three AFT implementation scenarios were analyzed using typical Calif. state and local pavement structures, and a federal study’s results were used to assess the effects on bridges. This study found that more NGV, EV, and FC trucks are expected among short-haul and medium-duty vehicles than among...”
    Posted 1/4/2021.
  • New Policy Brief Published: Heavier Alternative Fuel Trucks Are Not Expected to Cause Significant Additional Pavement Damage. “Medium- and heavy-duty trucks on California’s roads are shifting from conventional gasoline and diesel propulsion systems to alternative fuel (natural gas, electric, and fuel cell) propulsion technologies, spurred by the state’s greenhouse gas (GHG) reduction goals. While these alternative fuel trucks produce fewer emissions, they are also currently heavier than their conventional counterparts. Heavier loads can cause more damage to pavements and bridges, triggering concerns that clean truck technologies could actually increase GHG emissions by necessitating either construction of stronger pavements or more maintenance to keep pavements functional. California Assembly Bill 2061 (2018) allows a 2,000-pound gross vehicle weight limit increase for near-zero-emission vehicles and zero-emission vehicles to enable these trucks to carry the same loads as their conventional counterparts. The law also asked the UC Institute...”
    Posted 1/4/2021.
  • Fall 2020 Kent Seminar Led by UCPRC Director John Harvey: Improving Pavement Sustainability Through Integrated Design, Construction, Management, LCA and LCCA. On September 28, 2020, UCPRC director, Prof. John Harvey, delivered an online address to an audience at the Illinois Center for Transportation. His discussion focused on how to improve pavement sustainability through a broad approach that considers integrated design, construction, management, LCA, and LCCA. In his presentation, Prof. Harvey laid out the UCPRC research road map and the UCPRC research, development, and implementation vision he put together 20 years ago. He provided specific examples—including the use of CalME and performance-related specifications to design and implement long life asphalt pavements. He also talked about the use of LCCA and LCA to support state and local government decisions to evaluate alternative technologies to improve sustainability.
    Posted 12/9/2020.
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Summer 2021 UCPRC Activities

Candidate for fully permeable shoulder retrofit validation site

2020-2021 UCPRC Update. During the pandemic, the UCPRC has continued working with its clients and partners by following established safety guidelines. Among the Center’s ongoing work are the two projects described below.

First Project (3 photos). ADDING IN-PLACE RECYCLED MATERIALS DATA TO THE CalME DESIGN SOFTWARE. As part of a project to update the standard materials library in the CalME pavement design software, the UCPRC collected samples and performed field testing on state and local pavements that include partial-depth and full-depth recycled material. UCPRC staff conducted these activities from August through October 2020, visiting 21 state highway and local road pavements. Data from the test results were added to CalME’s materials properties database, and used to improve and calibrate the software’s FDR and PDR performance models. This augmented database puts Caltrans at the forefront of implementing asphalt pavement in-place recycling designs.

Second Project (7 photos). UCPRC SUPPORTS CALTRANS CAPITOL CITY CORRIDOR PROJECT. Paving on the Sacramento I-5 Capitol City (Cap City) Corridor Project wrapped up for the 2020 paving season in December and will resume spring 2021. The project reaches from its southern end south of Elk Grove Boulevard and extends north to the American River Viaduct in Caltrans District 3 (Post Miles 9.7 to 24.9). The UCPRC is serving as a research and quality assurance consultant on the project, aiding both Caltrans HQ and North Region Construction. Construction began in fall 2019 and is scheduled to end in 2022 (roughly 440 working days). The project was awarded in March 2019 to a joint venture between Granite Construction and Teichert Inc. with the winning bid for approximately $275 million. Notably, the project is the first in California and the US that will use performance-related testing as part of daily construction quality assurance, not just in mix design approval prior to construction.

Among the UCPRC’s contributions to the project are the performance-related specifications it developed for the project’s approximately 350,000 tons of long-life, hot mix asphalt, and the mechanistic-empirical software program CalME that Caltrans District 3 used to design the long-life pavement structure.

Prior to the 2020 paving season, the UCPRC also tested and approved seven project-specific mix designs that were used to construct the three-layer long-life pavement (LLP) system used in the project.

During the break between paving seasons, the UCPRC is conducting a review and re-verifying the 2020 mix designs before the 2021 paving season begins. The results of the project will be used to improve the current performance-related specifications (PRS), including the sampling and testing approaches. UCPRC staff will also continue to support District 3 with construction testing until completion of the project.