Contributions of Concrete Recycling Technology toward Sustainable Development: Standards and Technologies Related to Recycled Aggregate Concrete in Japan

Concrete is durable and can last for centuries. The waste from demolished concrete structures can be reused to reduce the environmental burden during their life cycle and ensure economic use of the construction resources. This study aims to improve the use of recycled aggregates prepared using the aggregate replacement method, effectively reducing both the environmental burden and costs associated with concrete waste. A high-value recycling method should be developed for concrete waste that offers improvements in terms of resource diversion and environmental preservation. New uses of concrete waste should be sought to counter the expected increase in the production of concrete waste with newer construction projects. Concrete waste contains harmful trace elements due to the use of cement, such as hexavalent chromium and lead. The most promising alternative materials are recycled aggregate concrete prepared using the aggregate replacement method, the uses of which are confined to concrete prepared from original mortar and/or original cement paste that contain toxic substances such as hexavalent chromium. The results of this study provide evidence for the effectiveness of using low-quality recycled aggregate concrete, such as of Class L, specified in the Japanese industrial standard (JIS) directive (JIS A 5023)