| abstract |
(57) [Summary] [PROBLEMS] Even if premixed, the water absorption function of smectite type clay mineral is not impaired. After kneading with water, it becomes a backfill material having a predetermined viscosity and bleeding rate, and exhibits a predetermined strength after curing. It can be prepared quickly at the construction site and does not cause mixing errors by workers. Even if the temperature at the time of curing changes, a stable curing time can be obtained. SOLUTION: It is prepared by uniformly mixing a smectite-type clay mineral such as bentonite, cement, a hydraulic substance, a filler, a thickener and a setting retarder in a predetermined ratio. The set retarders include citric acid and tartaric acid or their salts. |