Behavior of a hot mix asphalt made with recycled concrete aggregate and crumb rubber

Abstract

An experimental program was devised to evaluate the effect on the resistance of a hot mix asphalt, due to the total replacement of a natural aggregate (limestone — LS) by a recycled concrete aggregate (RCA). Two asphalt binders were used: conventional AC 50-70 (penetration grade) and AC 50-70 modified with crumb rubber (CRM). The mechanical properties investigated were the stability and flow ratio (Marshall test), indirect tensile strength, resistance to abrasion (Cantabro test), resilient modulus, resistance to permanent deformation, to fatigue and to moisture damage (modified Lottman test). When the LS is completely replaced by RCA, the resistance under monotonic loading, moisture damage and permanent deformation improved, the mass loss in the Cantabro test and the resilient modulus shows appropriate values, however, the fatigue resistance decreases. Besides, mixtures with RCA using CRM binder showed lower fatigue life under stress controlled tests, but much better rutting resistance.