Dissemination of technic for concrete using low-quality recycled aggregate to achieve a sustainable environment: examination on design method and validity of recycled aggregate concrete

Abstract

Many resources are used in the concrete-related sector to construct civil engineering buildings. Therefore, using the various by-products for resource circulation throughout the lifecycle of the concrete-related sector is critical to building a sustainable society. This study focuses on resource recycling, low carbon emissions, and environmental safety as means to building a sustainable environment in order to reinforce concrete works, particularly in civil engineering buildings. It also presents the examination results of the design method and validity for the active use of low-quality recycled aggregate concrete to decrease waste generation, reduce CO₂ emissions, and ensure environmental safety. Consequently, it was confirmed that the water–cement ratio could be set on the basis of safety reasons for the production of recycled aggregate concrete-Class M using the aggregate replacement method at all ready-mixed concrete factories. This was achieved by employing the strength reduction ratio obtained from the difference between the relative water absorption of normal-weight concrete and that of recycled aggregate concrete.