Construction and Performance of Shoulders Using UNRAP Base

Abstract

Construction of shoulders using untreated reclaimed asphalt pavement (UNRAP) represents a new construction technique for Florida Department of Transportation (FDOT) and other DOTs throughout the country. The objective of this study was to provide practical guidelines that can be used in constructing shoulder base courses with UNRAP material. Field and laboratory tests were performed to determine the physical and mechanical properties of UNRAP material. The results suggest the UNRAP material is well graded and its maximum dry density is comparable to those of other conventional granular materials. However, the optimum moisture content for UNRAP is much lower than that for conventional granular materials. The in-place strength of UNRAP base, as postulated from the Dynaflect test results, is on the order of 70–85% of the strength of the limerock base. The use of UNRAP base in constructing paved shoulders was found to be an economically and technically feasible alternative to traditional limerock. Additional theoretical and experimental studies as well as new test procedures to assess strength characteristics of UNRAP are warranted.