Performance Evaluation of Full Depth Reclaimed Mixes with Varying RAP Incorporation Levels

Full depth reclamation (FDR) of deteriorated pavement structures has been an emerging rehabilitation strategy adopted by road agencies in India. Scarcity in the availability of good quality aggregates, excessive haul distance, and availability of sufficient pavement crust material which are recyclable makes FDR, a more attractive option for pavement designers. Conventionally, routine maintenance of most of the road infrastructure is carried out by placing thin bituminous overlays. Thus, in FDR, it is possible that the reclaimed material can consist of higher percentage of recycled asphalt pavement (RAP) materials along with granular layer material and subgrade soil. When cementitious FDR process is adopted, it is worth investigating the performance of FDR mixes with varied level of RAP incorporation. In the present study, the FDR mix was studied at two levels of RAP incorporation 30, and 70%, along with a control mix (having no RAP content). Superpave Gyratory compactor was used for the mix design process. The study evaluated compressive strength, durability, flexural strength and fatigue characteristics of FDR mixes. Flexural strength of the beams showed a reduction in resilient modulus from 2900 to 1300 MPa with increment in RAP percentage. By utilizing fatigue equations developed in the study and elastic layered analysis using IITPAVE software, mixes incorporating higher RAP content had higher fatigue life for FDR layer thickness less than 160 mm, whereas for pavement sections with FDR layer thicknesses beyond 160 mm, pavements incorporating control mix and lower RAP incorporation (30%) had higher fatigue life.