Laboratory and Field Evaluation of RAP for Cement Concrete Pavements

In the present study, the feasibility of coarse reclaimed asphalt pavement (RAP) for dry lean concrete (DLC) and pavement quality concrete (PQC) mixes is assessed through laboratory and field investigation. Two kinds of RAP aggregates, namely RAP1 and RAP2 obtained from two differently aged pavements (10 and 20 years) were used for the present investigation. The properties of aggregates and concrete mixes were investigated in the laboratory and based on the results, 100% replacement of natural aggregates by RAP1 in the DLC layer and 65% replacement by RAP2 in the PQC layer was carried out. Additionally, one control slab was constructed. It was found that for achieving the suggested strength, RAP1-inclusive DLC mixes required at least 50% extra cement quantity. Similarly, incorporations of RAP2 was found to reduce the compressive strength of the PQC mix; however, the percentage reduction in flexural strength was comparatively lower. Structural evaluation through falling weight deflectometer provided with similar findings. Incorporation of RAP2 was found to increase the porosity of the slab but found to have a beneficial effect in terms of lower temperature differential. The combined stresses on the pavement slab were found to be either comparable or slightly lower in RAP-inclusive pavement as compared with the control slab.