Behavioural Study of Incorporation of Recycled Concrete Aggregates and Mineral Admixtures in Pavement Quality Concrete

The following is an in-depth study discussing various aspects of a sustainable Pavement Quality Concrete (PQC) mix with inclusion of Recycled Concrete Aggregates (RCA) and mineral admixtures. In addition to investigation of basic mechanical properties; compositional, morphological and interspatial aspects of hardened concretes were analysed to understand the macro and micro level effects of incorporating fine particulate fly ash, rice husk ash or bagasse ash in concrete mix having recycled concrete aggregates using state of the art techniques such as X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Mercury Intrusion Porosimetry (MIP). The study of PQC mixes prepared with assimilation of RCA and mineral admixtures show that addition of particulate mineral admixtures significantly enhanced the compressive and flexural strength of the mix incorporating RCA to the order of 15% and 25%, respectively. The study concluded that admixing mineral admixtures at 15% dosage refined the pore structure by reducing the average pore size by up to a few microns and also reducing the total pore volume which indicates towards the concrete mix being less permeable. This refinement in pore structure of concrete mix resulted in reduced water absorption and higher density values thus indicating improvement in durability of concrete.