Abstract
The study for using as recycle the cementitious powder consisting among the waste concrete, which accounts for more than 60%, could be achieved by authors. However, many practical problems that the lack of compressive strength due to internal fine aggregate and becoming free lime due to imbalance of raw chemical ingredient remain. In this study, promote a high quality of play cement with cementitious powder from waste concrete, blast furnace slag and fly ash as sub material to development recycled cement in the way of $700^{\circ}C$ low-temperature heating. As a result, the fluidity test of recycled mortar using recycled cement, the composition of recycled cement to slaking by CaO greatly reduced by sub material added result in increased liquidity. And also, recycled cement with blast furnace slag as sub material is more superior in improvement of compressive strength than without adding cement.
