CEMENT ADMIXTURE AND CEMENT COMPOSITION

PROBLEM TO BE SOLVED: To provide a cement admixture and a cement composition that give a good expansion strain without pop-out even when addition of a shrinkage reducing agent is suppressed.SOLUTION: There are provided a cement admixture (1) that includes free lime, a hydraulic compound, anhydrous gypsum, and an expanding agent having 40 mass% or more of a residue on 45 μm sieve and 30 mass% or less of a residue on 90 μm sieve; a cement admixture (2) that is the cement admixture (1) further including the shrinkage reducing agent; a cement admixture (3) that is the cement admixture (2) including 80-95 pts.mass of the expanding agent and 5-20 pts.mass of the shrinkage reducing agent; a cement admixture (4) that is the cement admixture (2) or (3) of which the shrinkage reducing agent contains an alkylene oxide/propylene oxide copolymer and a polyoxypropylene monoalkyl ether; and a cement composition (5) including cement and cement admixtures (1) to (4).