Patent ID: 6228962
Filing Date: 2001-05-08
Classification: C04B,C08L

Abstract:
A method of producing concrete, said method comprising the steps of preparing a cement dispersant and mixing cement, water and said cement dispersant at water-to-cement weight ratio of 20-40%, said cement dispersant comprising Component (a) and Component (b) at weight ratio ((a)/(b)) of 99/1-70/30, wherein Component (a) is a water-soluble vinyl copolymer with number average molecular weight 3500-50000, having as constituent units Unit A shown below by Formula (1) by 55-80 molar %, Unit B shown below by Formula (2) by 2-25 molar %, Unit C shown below by Formula (3) by 3-20 molar % and Unit D shown below by Formula (4) by 1-15 molar %, Units A, B, C and D totaling 100 molar %, and wherein Component (b) is another water-soluble vinyl copolymer with number average molecular weight 1500-25000, having as constituent units Unit A shown below by Formula (1) by 45-80 molar %, Unit B shown below by Formula (2) by 2-15 molar %, Unit C shown below by Formula (3) by 4-20 molar % and Unit E shown below by Formula (5) by 10-40 molar %, Units A, B, C and E totaling 100 molar %, Formulas (1)-(5) being as follows: ##STR2##where R.sup.1, R.sup.2 and R.sup.3 are each either H or CH.sub.3, R.sup.4 is an alkyl group with 1-3 carbon atoms, M.sup.1 and M.sup.2 are each an alkali metal, an alkali earth metal, ammonium or an organic amine, m is an integer 51-105, and n is an integer 5-25.