Cement compsns. with improved modulus at break - contg. hydraulic cement, water, polymer dispersible in water, and fine aggregate

摘要

Homogeneous unhardened cement compsns. contain (a) a hydraulic cement, (b) water, (c) a polymer dispensible in water, and (d) a fine aggregate, of which 75% passes through a sieve of 1-mm mesh. They have (i) wt. ratio b/a=10-28:100 (esp. 15-25:100), (ii) cpd. (c) chosen according to the nature of (a) and the propns. of (a), (b) and (d) to facilitate homogenisation, thereby yielding a prod. which can be shaped under pressure and which retains its form and (iv) wt. ratio c/a = 0.1-3.0;100 (esp. 0.5-2.0:100). The form constituents are subjected jointly to homogenisation and are possibly subjected to a shaping process which, by hardening and drying, gives a prod. of breaking modulus >20 MN/m2 (esp. >30 MN/m2). The hardened compsns. have higher modules at break than previously known compsn. and improved retention of modulus at break after weathering. Inclusion of fibres. (esp. nylon and polypropylene) improves shock resistance.