Investigation on mechanical properties and failure criterion of multi-recycled aggregate concrete under triaxial compression

Abstract

This paper presents a pioneering experimental investigation on the effects of lateral confining pressure and recycling cycles on the mechanical properties of natural aggregate concrete (NAC) and 3 generations of multi-recycled concrete (Multi-RAC) subjected to triaxial compression. The results indicate that both lateral confining pressure and recycling cycles have a significant influence on the triaxial mechanical characteristics of Multi-RAC specimens. The peak stress and peak strain increase with the increase of lateral confining pressure. Although the strength of Multi-RAC is inferior to NAC, the 2nd and 3rd generations present a relatively smaller downward trend compared to the 1st generation. The deformation ability of Multi-RAC is larger than NAC, especially for the 1st and 2nd generations. The elastic modulus of the 1st and 2nd generations are smaller than the counterparts of NAC and the 3rd generation. Based on experimental data, a failure criterion is proposed for Multi-RAC with proper consideration of the effects of the lateral confining ratio and the number of recycling cycles. The related outcomes are expected to provide the reference for safe engineering design and facilitate the structural application of Multi-RAC.