ABSTRACT
Greater utilization of recycled aggregate concrete is desirable to realize a sustainable society. To achieve sustainable, it is necessary to clarify the factors that reduce the strength and mass transfer resistance of low-quality recycled aggregate concrete and to develop technologies to improve these factors. In this study, the porosity in the concrete and its effect on each property were identified using a variety of coarse aggregates in order to identify the porosity in recycled aggregate concrete that leads to a reduction in strength and mass transfer resistance. The results show that low-quality recycled aggregate concrete has reduced strength and mass transfer resistance due to increased porosity in the new mortar and at the interface between the aggregate and the new cement paste. A C-S-H type accelerator agent was used as a solution to this problem. Strength and mass transfer resistance of low-quality recycled aggregate concrete were improved by the use of a C-S-H type accelerator.
