| 摘要 |
PROBLEM TO BE SOLVED: To obtain a cement admixture for grouts, capable of reducing the flowing of the grouts even under the conditions of high temperatures by including a specific expanded substance and a polycarboxylic acid polymer having carboxyl groups and polyalkylene oxide structures in side chains. SOLUTION: CaO raw material, Al2 O3 raw material and CaSO4 raw material are mixed in a CaO/Al2 O3 molar ratio of 6.5-18 and in a CaSO4 /Al2 O3 molar ratio of 1.5-4 and subsequently sintered at 1,100-1,600 deg.C to obtain an expanded substance having a Blaine value of >=4,000 cm2 /g, preferably 5,000-9,000 cm2 /g. The cement admixture for grouts comprises the expanded substance, 0.5-15 pts.wt. of a polycarboxylic acid polymer having a mol.wt. of 3,000-50,000, preferably 3,000-100,000 and an average particle diameter of >=1,000μm, preferably >=500μm, and having carboxy groups and polyalkylene oxide structures in side chains and, if necessary, >=13 pts.wt. of a fluidizing agent and/or 0.01-10 pts.wt. of a defoaming agent, wherein the total amount of the components is 100 pts.wt. |
