| 摘要 |
PURPOSE:To prevent the damage of a block completely by handling, and to remove washing mottlings by washing by coating the surface of the block immediately after instantaneous mold-release with a cement hydration reaction retarder mainly comprising mixed saccharides and washing the surface by water. CONSTITUTION:A surface layer 20 is formed onto a concrete rear layer 10, a plate is molded through press molding, the surface of the surface layer is coated with a retarder immediately after the molding of the plate, and the retarder is cured for a fixed time at a specified temperature. Concrete in a section not coated with the retarder is cured sufficiently, and uncured cement mortar is washed off by high-pressure injection or water washing by a brush from the surface of a block coated with the retarder and aggregate (seed stone) mixed in concrete is exposed. The retarder is obtained by further diluting an aqueous solution, which is blended with a 10-90 pts.wt. monosaccharide such as glucose, a 10-90 pts.wt. disaccharide such as maltose, a 0-40 pts.wt. trisaccharide such as maltotriose and a 0-40 pts.wt. polysaccharide higher than a tetrasaccharide such as tetraose, at 0.05-45wt.%. |
