Application of recycled coarse aggregate by mixture to concrete construction

With regard to the technology for producing aggregate of recycled concrete from concrete blocks, a great deal of research and studies have been reported, and the standard specification was drafted by the Ministry of Construction of Japan in 1996. However, it has hardly been applied to actual structures because of the high cost for production.The authors have developed a production method for recycled concrete that is different from that of the draft. The recycled coarse aggregate is produced by a simple assembled system of equipment, and is mixed with ordinary coarse aggregate to ensure the quality required of structural concrete. In this research, characteristics of strength, durability, fire-resistant property, structural performance, and workability of the recycled concrete are investigated. The necessary data for establishing a mix proportion design and a quality control method are obtained. In addition, a production method for the recycled concrete which has no use of a batching plant is proposed. Eventually, the economics and environmental loads of the developed method are evaluated and its effectiveness is confirmed.