Use of Reclaimed Asphalt Pavement and Recycled Concrete Aggregate for Bituminous Paving Mixes: A Simple Approach

Abstract

The present study is an attempt to explore the use of reclaimed asphalt pavement (RAP) and recycled concrete aggregates (RCA) in dense bituminous macadam (DBM) mixes in a simple approach to the readjustment of the gradation of RAP aggregates with RCA and the modification of RAP bitumen by treatment with conventional low viscosity grade (VG) bitumens, namely, VG10 bitumen and VG30 bitumen. The primary objective of this study is to design the mix containing RAP, RCA, and low viscosity bitumen so as to have satisfactory characteristics. Based on penetration tests, corroborated by other tests, the optimum proportions of the VG30 bitumen or VG10 bitumen and RAP bitumen, are found to be 70∶30 and 60∶40, respectively. The modified RAP mixes are found to result in, respectively, a 22% and 28% increase in the Marshall stability as compared with the control mix. It is also seen that the RAP modified mixes in general satisfy all requirements of Marshall and moisture susceptibility criteria. Furthermore, the indirect tensile strength (ITS) of RAP modified mixes with the RCA show a direct relationship with the temperatures, indicating an advantage over the conventional mixes.