| 摘要 |
PURPOSE:To densely deposit a concrete over the entire area of a mold flask by mixing a cement, a fine aggregate and a mixing agent for concrete and after adding and kneading water and a water reducing agent, feeding to knead a coarse aggregate in a concrete plant mixer to dispense with or minimize the tamping work at the time of depositing. CONSTITUTION:The mixing agent for concrete is obtained by combining (A) 100 pts.wt. mineral fine powder (e.g. calcium carbonate) 7000-20000cm<2>/g in specific surface area, (B) 1-10 pts.wt. mineral coarse powder (e.g. Portland cement clinker) 500-4000cm<2>/g in specific surface area, (C) 0.26-2 pts.wt. separation reducing agent composed of the cellulose based compound (e.g. water-soluble cellulose ether) and (D) 0.5-25 pts.wt. gypsum anhydrite powder 3000-7000cm<2>/g in specific surface area. The concrete is prepared by sufficiently mixing the cement, the aggregate and the mixing agent for concrete and after that, adding water to knead and adding the water reducing agent (e.g. highly condensed triazine derivative) and kneading again. |
