University of California Pavement Research Center

The work presented in this report is a summary of a series of research projects, whose central purpose is to support the Caltrans Quieter Pavement Research Program, which has as its goals and objectives the identification of quieter, smoother, safer, and more durable pavement surfaces. The research has been carried out as Partnered Pavement Research Center Strategic Plan Elements (PPRC SPEs) 4.16, 4.19, and 4.27. In the study documented in this report, field data regarding tire/pavement noise, surface condition, ride quality, and macrotexture were collected over four consecutive years from pavements in California placed with open-graded and other asphaltic mixes. The four-year data were analyzed to evaluate the durability and effectiveness of open-graded mixes in reducing noise compared to other asphalt surfaces, including dense- and gap-graded mixes, and to evaluate the pavement characteristics that affect tire/pavement noise. The analysis in this report is a supplement and update to two previous studies on the first three years of data collected, which are detailed in two separate reports prepared as part of PPRC SPE 4.16 and PPRC SPE 4.19, the previous phases of the Quieter Pavement Research Program, and documented in the reports for Partnered Pavement Research Center Strategic Plan Elements 4.16 and 4.19 for the first and second, and third years, respectively. Conclusions are made regarding the performance of open-graded mixes and rubberized mixes (RAC-G), comparisons are made with dense-graded mixes (DGAC), and the effects of variables affecting tire/pavement noise are examined.