Investigating the mechanical properties of roller compacted concrete pavement containing recycled concrete aggregates

In this study, some mechanical properties of roller compacted concrete (RCC) containing recycled concrete aggregate (RCA) have been investigated. Different mixtures of RCC, in which the fine, coarse or fine and coarse fractions have been replaced with RCA have been made and their mechanical properties including compressive strength, flexural strength, elastic modulus and energy absorption have been evaluated. The compressive and flexural strength of the mixtures have been measured at the different curing ages of 7, 28 and 91 days, while the elastic modulus and energy absorption have been evaluated on the specimens cured for 28 days. Results show that the mixtures containing RCA have a slightly less compressive strength than the control mixture made of natural aggregate. The highest compressive strength was obtained for the mixture containing recycled coarse fraction and natural fines. The flexural strength test results showed that the mixtures containing recycled aggregates have a higher flexural strength than the control mixture, with the highest flexural strength for the mixture containing coarse RCA and natural fines. Furthermore, the ratio of flexural to compressive strength, which is used as an indicative of energy absorption, is higher for the mixtures made of RCA, with the highest for the mixture containing both fine and coarse RCA. The elastic modulus test results show that the mixtures containing RCA have a higher energy absorption than the control mixture, while their elastic modulus is less than the that of the control mixture. The lowest elastic modulus was obtained for the mixture containing both coarse and fine fraction of RCA. This research results show that RCA obtained from structural concrete is feasible to be used in RCC.