Resilient moduli of a naturally aged RAP and aggregate blend

This paper presents the results of a study performed to characterize the resilient moduli of an unbound subbase material containing reclaimed asphalt pavement (RAP) that was placed in the 1980s. The Rhode Island Department of Transportation (RIDOT) is moving toward the use of the Mechanistic-Empirical Pavement Design Guide (MEPDG) for pavement design. This study characterizes the resilient moduli of a RAP/aggregate blend sampled from the existing roadway subbase layer along a segment of Route 165 in Rhode Island. The RAP/aggregate blend was placed during a previous resurfacing project performed in the 1980s and therefore has been in service for approximately 30 years. The material is a well graded mixture of sand and gravel-sized particles. Reconstituted test specimens were compacted at their optimum water content and to a relative compaction between 91% and 97%. The RAP content of the samples ranged from approximately 15% to 40%. The test results showed that the resilient modulus increased with bulk stress, yielding resilient modulus values of 120 MPa to 513 MPa. Resilient modulus was not affected by changes in relative compaction within the range tested. An increase of RAP content from 15% to 40% increased the resilient modulus by approximately 15%. © 2014 American Society of Civil Engineers