| 摘要 |
PURPOSE:To obtain the title concrete of enhance quick-setting effect without impairing the fluidity of concrete by incorporating, in advance, kneaded concrete with a specific polycarboxylic acid-based admixture and a quick-setting agent. CONSTITUTION:In a concrete-covering construction procedure to apply kneaded concrete incorporated, in advance, with a quick-setting agent on the drilled surface of the underground hollow space or tunnel, concrete to be kneaded is incorporated, in advance, with a polycarboxylic acid-based admixture consisting mainly of a copolymer containing, in part of its molecular structure, carboxyl-substituted vinyl monomer. Said admixture is e.g., a copolymer form alpha,beta-unsaturated dicarboxylic acid and olefin, a second copolymer from polyethylene glycol monoallyl ether, maleic acid-based monomer, and another monomer copolymerizable therewith. The amount of this admixture to be used is suitably 0.01-0.5wt.% (on a solid basis) based on the weight of cement. |
