| 摘要 |
<p>Process comprises addn. to the fresh concrete of 0.5-1 percent relative to the cement weight, of an aqueous solution contg. 1-4 parts/thousand polyvinyl pyrrolidone as non-inorganic protective colloid, and 0.8-1.2 of phosphoric acid butyl ester. After hardening in a mould, the temperature of the concrete is lowered several deg.C relative to room temp. over one hour. - The addn. is made to the powder form concrete mix, in conjunction with plasticising, sealing, pore-forming, accelerating and retarding agents. (0/0)</p> |
