The effects of the quality of recycled aggregates on the mechanical properties of roller compacted concrete

Abstract

This study investigates the performance of roller compacted concrete (RCC) made with recycled aggregates derived from crushed demolished concrete with various proportions of natural. The experimental study examines substituting various proportions of natural aggregate (3/8, 8/15, and 15/20) with recycled aggregate. The replacement rates range from 0% to 100% in increments of 25%. Eleven different mixtures have been made by changing the amount of recycled aggregate used, with and without pre-wetting, before being added to concrete. Additionally, 5% of the cement content was substituted with silica fume and slag in each composition. An experiment test was done to see how recycled aggregate-based BCRs' performance changed with the incorporation rate on fresh and hardened concrete's mechanical and physical properties. Physical parameters, including volume masse, vebe time consistency, and mechanical properties such as compression resistance, flexion resistance, and ultrasonic pulse speed, were measured over time. The results found were compared to the control mix made with 100% natural aggregates. Those results show that as the replacement rate increases, the water absorption rate increases with a decrease in mechanical strength. In addition, the pre-wetting treatment did not significantly impact mechanical strength. This can be explained by the characteristics of the recycled aggregate, such as high absorption, low resistance to wear, and low density, which were caused by the residual paste adhered to the recycled aggregate.