Evaluation of cement treated reclaimed asphalt pavement and recycled concrete pavement bases

Abstract

Cement stabilization is the most frequently used technique to enhance the mechanical properties of recycled materials. Reclaimed Asphalt Pavement (RAP) and Recycled Concrete Aggregate (RCA) are abundantly available recycled materials and utilization of these materials in road construction is a sustainable and eco-friendly process. However, the advantage of cement stabilization of RCA over RAP and blending with Conventional aggregates (VA) as a base and subbase course material at different stabilization levels is unknown. In the current study the same is investigated by stabilizing mixes with cement contents varying from 2 to 6% and blending with VA compared in terms of physical properties, compaction characteristics, and the performance tests like Unconfined Compressive Strength (UCS), Indirect Tensile Strength (ITS), and Modulus of Elasticity (E) at 7 days of curing period. From the results, it is observed that recycled aggregate blends need higher cement contents to satisfy the specifications as base layer for high volume roads and the stabilization of RCA is more pronounced compared with RAP. Significant improvement in strength is observed when blended with VA at all cement contents. However, RCA mixes achieved maximum strength at equal proportions of RCA and VA. No particular trend is observed in Optimum Moisture Content (OMC) and Maximum Dry Density (MDD) for RCA blends due to the non-homogeneous distribution of mortar. The Elastic modulus of the RCA mixes declines with RCA content at higher cement content due to brittle nature. Summarily, 25% RAP, 25% RCA and 50% RCA blends at 6% cement performed well.