Water-reducing admixtures for cementitious compositions.

摘要

An admixture for decreasing the water demand of cementitious compositions such as concrete consists of (a) from 75-25% by weight of a water-reducing agent whose major component is a polycarboxylate; and (b) from 25-75% by weight of at least one saccharide component selected from hydrogenated saccharides and polyhydric alcohol adducts of saccharides. The saccharide component is preferably a hydrogenated polysaccharide with a molecular weight distribution as follows: (i) 70-30% by weight (on total weight of hydrogenated saccharides) have molecular weights in the range 180-300; (ii) 30-70% by weight have molecular weights of from 300 up to 4,000; and (iii) 30% by weight maximum have molecular weights of 4,000 and over.