Influence of temperature on mechanical properties of recycled asphalt pavement aggregate and recycled coarse aggregate concrete

Abstract

The effect of fire on reinforced concrete (RC) structures is very important because it is threatening the human life and property safety. Using Recycled Asphalt Pavement (RAP) and Recycled Coarse Aggregate (RCA) in concrete mixtures can be considered economically and environmentally friendly because it saves our natural resources. This paper investigates experimentally the influence of incorporating RAP and RCA on the mechanical properties of concrete mixes after exposure to different temperatures: 20 °C, 200 °C, 400 °C, and 500 °C. The Natural Coarse Aggregate (NCA) was replaced by RAP aggregates at three replacement ratios (10%, 20% and 30%), and the NCA was replaced by RCA at four replacement ratios (20%, 40%, 60%, and 100%). As well as using three mixes of 90%RCA-10%RAP, 80%RCA-20%RAP, and 70%RCA-30%RAP. Compressive, splitting tensile and flexural strengths, compressive stress-strain curves, and modulus of elasticity were studied on two hundred sixty four cylinders and one hundred thirty two prisms. The results showed that the mechanical properties decreased as the replacement ratios of RAP and RCA increased for the same temperature. And the mechanical properties decreased for the same replacement ratio of recycled aggregates when the temperature increased. The decrease in mechanical properties at elevated temperatures for RAP-RCA mixes can be comparable with NCA, RAP and RCA only mixes. Therefore, the RAP and RCA have the potential to be incorporated in the concrete mixes on high temperatures since the decrease in the mechanical properties is not that significant relative to the efforts in reduction the negative impacts of recycled aggregates on the environment and human health.