Elucidation of Asphalt Characteristics Influencing Cement Mortar Constituted with Reclaimed Asphalt Pavement Aggregates

This study elucidates the role of asphalt binder coating of the reclaimed asphalt pavement (RAP) aggregates on the behavior of cement mortar. To fundamentally understand the role of asphalt binder, the fine RAP aggregates were prepared in the laboratory, varying the asphalt binder characteristics such as viscosity [100–400 Pa.s (1,000–4,000 Poise)], its content (film thickness of 6 and 8 μm), and aging intensity (short- and long-term). A direct correlation was found to exist between asphalt cohesive strength and mortar performance. Specifically, long-term aged binders were found to enhance the flexural strength by 3%–4%; upgrading binder grade from VG-10 to VG-40 increased the same by 19% while increasing film thickness from 6 μm to 8 μm decreased the strength by 16%. This study suggests that RAP derived from older pavements or those utilizing a stiffer asphalt binder yields enhanced concrete strength, in contrast to RAP from younger pavements or those with a softer asphalt binder.