Recently, Recycled materials have been widely used in the world because of the environmental consciousness. Recycled aggregates have different properties because of sources and manufacturing process. Aggregate quality is based on gradation, gravity, water absorption and water content. Especially cement mortar adhered amount on the aggregate surface has a significant impact. Recycled Aggregate Quality is based on Aggregate Absorption. The existing technology of Japan can produce high quality aggregate which similar to natural aggregate. The main purpose of the study is to investigate the newest technology of waste concrete in Japan, then assess the applicability in Taiwan.