Patent ID: 6024791
Filing Date: 2000-02-15
Classification: C04B,Y10S

Abstract:
A hardened cement body manufactured by a process comprising admixing a mixture consisting essentially of 98 to 80 parts by weight of a cementitious hydraulic powder, 2 to 20 parts by weight of a hydraulic powder precursor selected from the group consisting of silica fume, enameled frit, glass powder, aplite made of silicic acid rock and blast furnace slag, and having an average diameter of less than 3 microns, water and optionally a fine aggregate, to obtain a mortar, the water is added to a resulting mixture of the hydraulic powder precursor and the cementitious hydraulic powder such that a weight ratio of the water to the cementitious hydraulic powder is 0.15 to 0.35, to obtain a molded body, and subjecting the molded body to a two step curing comprising (a) precuring the molded body at a temperature of 20.+-.3.degree. C. for at least one day to form a hydrate of calcium silicate in the molded body and (b) curing at a temperature of 37.degree. C. to less than 100.degree. C. for 1 to 10 days to polymerize silicic acid anions in the calcium silicate hydrate to obtain a trimer or higher polymer, to form a glassy composition in fine pores of said hardened cement body, wherein the silicic acid anions being in an amount of at least 1.3 times greater than that of said hardened cement body and wherein said hardened cement body has a compression strength of at least 1000 kgf/cm.sup.2, and a bending strength of at least 150 kgf/cm.sup.2.