The damping property of recycled aggregate concrete

Damping property is one of the intrinsic dynamic characteristics of a material. Currently, open studies on the damping property of recycled aggregate concrete (RAC) are very limited. This paper investigates the effect of replacement percentage and size of recycled coarse aggregate (RCA) on the damping property of RAC. Three-point dynamic bending test of beams and free vibration damping test were respectively conducted to study the loss tangent of RAC in elastic stage and the damping ratio of a RAC cantilever beam in inelastic stage. The results show that either an increase in replacement ratio or a decrease in RCA size leads to an increase in the loss tangent and damping ratio. Compared with natural aggregate concrete (NAC), the improvement in damping property of RAC may be induced by a number of factors such as the sliding among the old and new interfacial transition zones (ITZs), the propagation of micro-cracks, the friction within micro-cracks and macro-cracks, the compression and expansion of air in voids existed in old mortar. It is concluded that the replacement percentage and the RCA size have a significant influence on the damping property of RAC.