Damping of rubberized recycled aggregate concrete and damping estimation of its elements by finite element analysis

Concrete structures inevitably suffer from dynamic loadings, causing damage and uncomfortable vibration. Improving the damping of concrete to passively absorb the vibration energy is beneficial to mitigate the hazards and improve comfort. However, at least two challenges must be completed before applying this strategy, namely, preparing effective energy dissipating concrete and estimating the damping parameter of its elements and structures. In this study, rubberized recycled aggregate concrete (RRAC), prepared with coarse recycled concrete aggregate (RCA) and recycled rubber aggregate (RRA) instead of natural aggregate, is experimentally validated to show higher damping. Besides, a universal function of energy dissipation over strain amplitude is established for concrete containing natural aggregate, RCA, and RRA. Based on the found strain-energy dissipation function and finite element analysis, an iterative method of estimating the inner damping ratio of RRAC elements from the material damping is proposed and validated. Through the proposed method, the effects of loading amplitude, loading frequency, and stress history on the nonlinear damping behaviors of RRAC beams are numerically analyzed. The experiment result and the proposed damping determination method can encourage the application of recycled building materials in structural engineering, especially in projects with requirements of vibration control.