Influence of new‐to‐old concrete interface on the damping behavior of recycled aggregate concrete

Abstract

AbstractThe interface transition zone (ITZ) is a critical component of concrete, as it has a significant effect on the material's mechanical properties. This paper using specimens of bonded new and old concrete analyzes the effect of the interface in recycled concrete on damping performance using semi precast concrete specimens with old and new concrete. To determine the effect of the bonding zone between new and old concrete on the damping ratio of recycled concrete, the free vibration attenuation test method was used. When the acceleration signal from the specimen's transverse vibration is transformed to the frequency domain, the study observes two prominent peaks. The damping ratio is between 0.005 and 0.007 at the high‐frequency position and 0.06–0.08 at the low‐frequency position. When the excitation position is not in the bonding zone, the damping ratio measured in the bonding zone has a smaller average value. Under different recycled aggregate replacement rates, there is a significant difference in the damping ratio and frequency of old and new concrete bonded specimens, as well as complete recycled concrete specimens. The bonding zone's damping ratio data is more discrete than that of other locations. The damping ratio and the acceleration amplitude exhibit an excellent linear relationship, with the damping ratio increasing as the amplitude increases. The damping ratio varies significantly more in the longitudinal direction, with no apparent relationship to the acceleration amplitude.