| 摘要 |
PROBLEM TO BE SOLVED: To provide a cement composition making small the volume of contraction of a hardened body such as cement, mortar and concrete and giving high bending/cracking strength to the hardened body. SOLUTION: This cement composition contains the polyoxyalkylene derivative shown by the general formula: X O(AO)nR}m, wherein X is a residual group of the compound having 2-8 hydroxyl groups; AO is a 2-18C oxyalkylene group; R is a hydrogen atom, a 1-18C hydrocarbon group or a 2-18C acyl group; n is 30-1,000; m is 2-8; an oxyethylene group accounts for 60% or higher of the AO and is used as a powdery drying and contraction-reducing agent so that the mass ratio of cement : an expanding material : the drying and constriction- reducing agent is 80-98:2-20:0.2-10. The expanding material contains released lime, calcium alumino-ferrite and anhydrous gypsum. |
