ULTRA HIGH-EARLY-STRENGTH EXPANSIVE ADMIXTURE FOR CONCRETE AND PRODUCTION PROCESS OF CONCRETE PRODUCT USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide an expansive admixture for concrete by the use of which concrete having required workability until placing of the concrete is completed can be obtained and, after the placing, the concrete can early be hardened to form high strength expansive concrete causing substantially no alkali- aggregate admixture. SOLUTION: The production process of this expansive admixture comprises steps of: pulverizing lumpy quick lime having a 70-500 ml 4N hydrochloric acid consumption value into powdery quick lime having a >=3,000 cm2/g Blaine specific surface area; and mixing 100 pts.wt. of the resultant powdery quick lime on the basis expressed in terms of CaO, 5-20 pts.wt. of powdery anhydrous gypsum II and a sufficient total amount of alkali sulfates to provide the ratio of the total alkali content (Na2O+0.658K2O) to the total amount of the resulting mixture of 0-0.75 (excluding 0) pts.wt, together.