| 摘要 |
<p>1354053 Portland cement RHONE-PROGIL 21 June 1972 [2 July 1971] 29107/72 Heading C1H A Portland cement contains, as setting accelerator, in weight per cent based on the weight of the cement: 0À5-5 alkali metal bicarbonate, 0À05-2 alkali metal or alkaline earth metal salt of a hydroxylic carboxylic acid, e.g. tartaric, gluconic, lactic, malic or salicylic acid, 0À5-5 alkali metal silicate, e.g. Na 2 SiO 2 , the ratio of silica to alkali metal oxide being between 0À5 and 4. Precipitated silica may also be included in the mixture.</p> |
