| 摘要 |
PROBLEM TO BE SOLVED: To produce a highly rigid cement having high compression strength, tensile strength, flexural modulus, and the like, by mixing an admixture comprising corundum of alumina containing chromium oxide or cobalt oxide, a gel of silicic acid and a glucose, with a cement. SOLUTION: This highly rigid cement contains corundum of alumina, a gel of silicic acid and a glucose as an admixture. The very hard and chemically stabilized corundum having crystals arranged in the constant direction is obtained by melting alumina containing chromium oxide and cobalt oxide and cooling the melted alumina. A water glass is obtained by adding water to sodium silicate obtained by melting silicon dioxide in the coexistence of a base, and heating the obtained mixture. A dilute hydrochloric acid is added to an aqueous solution of the water glass, and the resultant mixture is shaken to provide a gel. The obtained gel is dried to provide a xerogel, and the obtained xerogel is formed into a powder. The glucose is obtained by hydrolyzing a starch. The cement has reducibility and strong adhesion because the crystal of the glucose becomes an equilibrium state of alpha-glucose, beta-glucose and linear glucose, and aldehyde group is present. |
