Dynamic behaviour and energy dissipation of reinforced recycled aggregate concrete beams under impact

Abstract

Abstract In order to study the dynamic behaviour and energy dissipation of reinforced recycled aggregate concrete (RAC) beams under impact, four groups of reinforced RAC simply supported beams with various recycled coarse aggregate (RCA) replacement percentages are designed and tested under drop weight impact at the mid-span of beams and corresponding another four groups of beam specimens under static loading. The static resistance versus mid-span displacement curves are obtained from static loading test to analyse the effect of RCA replacement percentage on the beam's mechanical performance. It is concluded that the static resistance and stiffness of the RAC beam decrease slightly as the RCA replacement percentage increases and the deformation curve of reinforced RAC beam conforms to the classical bending theory of beam. In the drop weight impact test, the reinforced RAC beams failed with both global and local damage, and in bending controlled mode. The time history of impact forces, mid-span displacements and stress states of the beams are investigated. The mid-span displacement of the beams increases with the increase of RCA replacement percentage. The energy dissipation of the beams under impact is discussed based on the simplified resistance model. A concept of global damage energy dissipation is introduced and the method for calculating the global damage energy dissipation of the reinforced RAC beam under impact is proposed. The global damage energy dissipation ratio is defined and used to measure the proportion of global damage and local damage on reinforced RAC beam under impact. The experimental results presented here provide benchmark data for the further research work on the dynamic response of reinforced RAC beam under impact.