| 摘要 |
PROBLEM TO BE SOLVED: To obtain an additive which improves air entraining property and increases the early-stage strength and long-term strength of a cement-based hardened body by using an alkanolamine or its salt having ionic functional groups except hydroxyl groups and having at least two alkanol groups. SOLUTION: An alkanol amine or its salts, especially having at least one ionic functional group except hydroxyl groups and having at least two alkanol groups is preferably used. As for the ionic functional groups, for example, carboxyl groups, sulfonic acid groups, dicarboxylic acid monoester groups and sulfate monoester groups are preferable. For example, a compd. expressed by formula I (R1 , R2 are each H, 1 to 3C alkyl, R3 is 2-carboxyalkyl, hydroxycarboxylalkyl, 2-sulfoalkyl, hydroxysulfoalkyl (with 2 to 4 carbon atoms in the alkyl group)), by formula II (R is vinylene, phenylene, 2 to 6C alkylene) or formula III, and salts of these can be used. |
