Crushing behavior of recycled concrete aggregate on different materials

Abstract

This final year project aims to investigate the breakage behavior on distinct types of recycled concrete aggregate, and the influence of micro-mechanical properties on the behavior under single particle crushing test. Sydney (Red, White, Black) and Hong Kong recycled concrete aggregate were tested in this project. The research method performed in this project was modified based on the literature.

The single particle was placed between platens of the CBR (California Bearing Ratio) test machine and the data were recorded and monitored by the software Triax. In this project, the shortest and intermediate diameter were used to estimate the area when calculating the failure stress. The influence of minerology, size and shape were analyzed based on the result: (I) Force-displacement behavior, (II) Probability survival (III) Weibull distribution (m value).

The result showed that the (I) The displacement usually increased proportionally (non-linear) with the applied load, until it reached the peak and caused the sudden drop. 2 major types of force-displacement behavior were observed, and they are related to splitting mode. (II) Sydney Black had the highest probability of survival, followed by Hong Kong RCA, Sydney White RCA, and Sydney Red RCA respectively. The minerology had major influence on that. In general, the probability of survival increased with the crushing speed. (III) The Sydney White RCA had the lowest Weibull Modulus, no matter the change in crushing speed, indicating a large variation on the strength distribution.