SUBSTANCE HAVING HIGH HYDRATION ACTIVITY, ACCELERATOR FOR CEMENT AND METHOD FOR PROMOTING SETTING AND HARDENING OF CONCRETE OR MORTAR

摘要

PURPOSE:To obtain an accelerator for cement having excellent initial and long- term strength development by adding ZnO or BaO to a CaO-Al2O3 system to obtain a composition having a specific composition imparted with calcium aluminate hydration activity. CONSTITUTION:This accelerator for cement is a highly hydrating substance obtained by melting and quenching a CaO-ZnO-Al2O3 composition, containing 10-79wt.% of CaO, 1-30wt.% of ZnO and 20-60wt.% of Al2O3 based on the sum of CaO, ZnO and Al2O3 and containing 40-80wt.% of CaO and ZnO in total. BaO may be used as a substitute for ZnO. The highly hydrating substance may be incorporated with one or more kinds of substances selected from 5-35wt.% of gypsum, 5-40wt.% of lime, 5-50wt.% of an alkali metal carbonate, 10-50wt.% of sodium aluminate and <=25wt.% of aluminum hydroxide.