| 摘要 |
PROBLEM TO BE SOLVED: To provide a cement admixture and a cement composition which impart excellent antirust effects to inner reinforcing bars, have shielding effects against chloride ion permeation intruding from outside, and further can inhibit pore formation because of little leaching of Ca ion, exhibit excellent crack resistance because of small drying shrinkage, and further exhibit excellent durability over a long period because of having a self-healing effect of blocking generated cracks by itself, in a cement concrete hardened body.SOLUTION: A cement admixture contains a calcium ferroaluminate compound with a CaO/AlOmole ratio of 0.15-0.7 and an FeOcontent of 0.5-20 mass%, and water, where the amount of water is 0.1-3 pts.mass to 100 pts.mass of the calcium ferroaluminate compound. It is preferable that Blaine specific surface area is 2,000-7,000 cm/g. A cement composition includes cement and the cement admixture. |
