Effective recycling of surface modification aggregate using microwave heating

Abstract

In this study, Author present a quantitative review of the mechanical performance, as well as the separation from the matrix and the recovery performance of surface modification coarse aggregate (SMCA) that was produced using aggregate, whose surface was modified using fine inorganic powder. Therefore, experiments were conducted to measure the compressive strength, microwave heating characteristics, distribution of the void volume, and chemical changes in SMCA concrete, as well as the recovery rate of the aggregate. The results of the experiments showed that reinforcing the interfacial transition zone, which is a weak part in concrete, by coating the surface of the original coarse aggregate with cement paste, can help suppress the occurrence of microcracks and improve the mechanical performance of the aggregate. Further, microcracking and the decomposition of hydrates were observed as a result of microwave heating. In other words, an increase in void size distribution and weakening of the hydrated cement paste led to the effective recovery of recycled coarse aggregate. Copyright © 2014 Japan Concrete Institute.