CEMENT GENERATING SMALL AMOUNT OF GASEOUS AMMONIA, ESTIMATION METHOD FOR THE SAME AND CONCRETE GENERATING SMALL AMOUNT OF GASEOUS AMMONIA

摘要

PROBLEM TO BE SOLVED: To reduce the amount of gaseous ammonia generated from concrete at the stage of the production of a raw material by controlling the total amount of iron slag being mixed as a raw material and an additive for cement to be not more than a specified ratio and using, as gypsum to be added to the cement, titanium gypsum or desulfurization gypsum. SOLUTION: The total amount of iron slag being mixed as a raw material and an additive for cement is controlled to be not more than 70%. Paste samples are obtained by kneading cement and pure water in the ratio of 1:0.2 to 1:0.4 and are kept in a closed vessel at least three days. When the concentration of gaseous ammonia in the closed vessel is not more than 2 ppm, the cement is defined as the low gaseous ammonia generating cement. The low gaseous ammonia generating concrete is obtained by providing a composition composed of the cement generating a small amount of gaseous ammonia of 200 kg/m3 per unit weight, a fine aggregate from which an amount of =50 m/g of ammonium ion is eluted in an alkaline solution, and an AE water reducer or the like from which an amount of =100 m/g of ammonium ion is eluted in an alkaline solution and having the ratio of water to cement of 40 to 60%.