| 摘要 |
<p>PROBLEM TO BE SOLVED: To decrease contraction by drying from the initial drying stage of a cement to a long age and to prevent cracks in a hardened material by compounding one or more kinds of polyoxyalkylene compds. SOLUTION: As for the contraction reducing agent for a cement, one or more kinds of compds. selected from polyoxyalkylene compds. expressed by the formula are compounded by 0.1 to 10 wt.% of the cement. In the formula, AO is 3-4C oxyalkylene group and n is 1 to 10, and AO represents one of oxypropylene group, oxyisobutylene group, oxytetramethylene group or a mixture of these. If two or more groups are included, addition polymn. may be carried out as random addition or block addition polymn. If necessary, other additives for a cement can also be used.</p> |
