Influence of Curing Time on the Mechanical Behavior of Cold Recycled Bituminous Mix in Flexible Pavement Base Layer

Abstract

This study examined the mechanical behavior characteristics of cold recycled emulsified asphalt bases with RAP 76% and emulsified asphalt 3%, in different cure time, i.e., 0, 7, 14 and 28 days and evaluated in terms of the resilient modulus (RM) and permanent deformation (PD) based on repeated load triaxial tests. The results demonstrated that in the first 7 days, the RM increased by 80% compared to the freshly compacted material and after this period, the subsequent increases were not as significant, ranging, from 10.9% to 19.4%, that shows that initical cure time significantly influences the RM behavior of the mixtures. However, the mixtures showed considerable permanent deformations, even after 28 days of curing. This indicates that the use of asphalt emulsion, with prolonged curing, improves the mechanical properties of the mixture but does not entirely resolve the issue of permanent deformation in cold reclaimed asphalt mixture (CRAM). The plastic deformation behavior observed in the triaxial tests must be taken into account when designing pavements containing RAP and asphalt emulsion.