Utilization of reclaimed asphalt pavement (RAP) as granular sub-base material in road construction

Abstract

Currently, the scarcity of natural resources has been a significant impact on the construction industry. The demand for fresh aggregate becoming huge due to the increase in the construction of pavement and fulfilling the aggregate requirement is a great concern. In this research, an effort has been shaped to assess the feasibility of the use of Reclaimed Asphalt Pavement (RAP) material for improving the strength properties of the granular sub-base (GSB) layer. RAP aggregate was partially and fully replaced with fresh aggregate in different percentages to test various strength properties. Efforts were being made to improve the strength of the GSB layer by using RAP concerning soaked California Bearing Ratio (CBR) by blending with natural aggregates (NA). To know the best of mix proportions, RAP was partially and fully replaced with virgin aggregate in varying percentages such as 0%, 25%, 35%, 45%, 55%, 65%, and 75%. Modified compaction tests were performed on 100 % RAP and mixtures containing various percentages of RAP to establish the optimum water content for CBR sample preparation. Soaked CBR value was determined at 7 days, 14 days to see the effect of RAP on the GSB mixes. It was observed from the results that the soaked CBR value of RAP improves from 32% over 100% when it is mixed with natural aggregates in varying percentages and made it appropriate for utilizing it as a sub-base of flexible pavement. Depending upon the experimental outcomes, it was deduced that RAP in the sub-base layer is limited to 55% which has exquisite properties as natural aggregates utilized in the road sub-base.