This study was to investigate the reduction of hydration heat by utilizing industrial by-products such as BFS(Blast Furnace Slag) and FA(Fly Ash). DM(Dredged Mud) was used by parent soil and Ordinary portland cement was used by cementing material. Additives added to reduce the heat of hydration were BFS and FA. From the results of experiment, hydration heat was decreased in accordance with the addition of BFS and FA. The reason was that surface of BFS coated with aluminosulfate and FA is apt to uptake free Ca2+ ion, which has not created a nucleus of Ca(OH)2. Initial uniaxial strength was low, neither was not long term uniaxial strength. It was concluded that silica rich layer(H2SiO4 4-) in solid phase early in the reaction of hydration was difficultly moved in liquid phase due to the increase of ZP(Zeta Potential). However, the ZP in the later hydration was decreased due to the acceleration of mobility of silica rich layer(H2SiO4 4-). Therefore, long term physical properties such as uniaxial strength revealed.