Production of Roller Compacted Concrete Made of Recycled Asphalt Pavement Aggregate and Recycled Concrete Aggregate and Silica Fume

This research aims to evaluate the potential using of recycled asphalt pavement aggregate (RAP), recycled concrete aggregate (RCA) and silica fume (SF) in production of roller compacted concrete (RCC). Thirty RCC mixes were casted in which natural aggregates (NA) were totally replaced by RAP and RCA with (90% and 10%), (80% and 20%), (70% and 30%), (60% and 40%), (50% and 50%), (40% and 60%), (30% and 70%), (20% and 80%) and (10% and 90%), respectively, and cement was partially replaced by SF in 2% (2.5% and 5%). The tested mechanical and physical properties of RCC mixes were the compressive strength, tensile splitting strength, the modulus of elasticity, the modulus of rupture, and the density. The durability feature was monitored through the water absorptions of the RCC. Test results showed that partial replacement of cement with 2.5% and 5% SF has improved the mechanical properties of conventional RCC mixes, as well as, decreasing the dry density of RCC mixes and the water absorption of conventional RCC. Replacing the NA aggregates with RCA and RAP in RCC mixtures has decreased the mechanical properties such as compressive, splitting strength, flexural strength and modulus of elasticity. Even though the RCC reached the required compressive stress which would be used for public traffic or dams. Finally, as the high RCA content increased the water absorption increased which is the most significant indicator for durability of material, while the high RAP content decreased the water absorption.