| 摘要 |
PROBLEM TO BE SOLVED: To provide a cement admixture and a cement composition adding a superior rust-preventing effect to a steel rod in a cement concrete hardened body, having an effect of shielding chloride ions infiltrating from outside and neutralization inhibition effect and further suppressing pore formation because of little leaching of Ca ions. SOLUTION: There are provided (1) the cement admixture including a calcium aluminate compound having a molar ratio CaO/Al<SB>2</SB>O<SB>3</SB>of 0.15-0.7 and having a Blaine specific surface area of 2,000-7,000 cm<SP>2</SP>/g and a water reducer and having a blending ratio of the calcium aluminate compound to the water reducer of 5-1,000 pts.mass to 100 pts.mass calcium aluminate compound, (2) the cement admixture in which the water reducer is one or more selected from among a naphthalene sulfonate-formalin condensate, a melamine sulfonate-formalin condensate and a polycarboxylate-based polymer and (3) the cement composition including cement and the cement admixture. COPYRIGHT: (C)2010,JPO&INPIT |
