Effects of recycled concrete aggregate on stiffness and rutting resistance of asphalt concrete

The objective of this research was to assess the possibility of using recycled concrete aggregate (RCA) in asphalt mixtures. The experimental research included 10 asphalt mixtures with partial natural aggregate substitution by RCA, which ranged from 15% to 45% of fine (⩽4 mm), coarse (4/22.4 mm) and both fine and coarse aggregate. The optimum bitumen content increased with increasing RCA content. The use of RCA had no significant influence on the permanent deformation, while the stiffness modulus of asphalt mixtures with RCA was lower compared with the control mixture, especially at high frequencies. The results indicate that RCA can be successfully used in asphalt mixtures.