LOW SHRINKAGE CEMENT COMPOSITION

PROBLEM TO BE SOLVED: To reduce drying shrinkage of a cement composition and to effectively utilize and recycle a waste by incorporating a hydraulic composition prepared by adding gypsum into a fried material obtained by using >=1 kinds of a municipal refuse incineration ash or a sewage sludge incineration ash as raw materials. SOLUTION: The hydraulic composition (ecological cement) uses >=1 kinds of the incineration ash of municipal refuse or sewage sludge as the raw materials and is obtained by adding 1-30 wt.% gypsum into the 100 wt.% fired material containing 10-40 wt.% C3 A and >=1 kinds of C2 S and C3 S (C is CaO, S is SiO2 , A is Al2 O3 ) and pulverizing. In the case of adding the ecological cement into cement, the quantity to be added is controlled to >=40 wt.% and an organic shrinkage reducing agent of 0.5-0.6 wt.% is added to the mixture of both. The dry shrinkage factor of a cement composition using only the ecological cement is the same degree as that in the case of using a large quantity of a shrinkage reducing agent in a common Portland cement and the same shrinkage factor is attained with the addition of one-half of the quantity of the shrinkage reducing agent in the case of mixing equal quantity of the ecological cement and the common Portland cement.