WHITENING PREVENTIVE FOR MORTAR OR CONCRETE AND WHITENING PREVENTIVE METHOD

摘要

PURPOSE:To prevent e.g. mortar from whitening without losing its fluidity and initial mechanical strength by incorporating cement with a specified amount of a whitening preventive comprising KAlO2 and noncrystalline hydrous alumina of specific disposition at specified ratio. CONSTITUTION:The objective whitening preventive comprising (A) such noncrystalline hydrous alumina as to dissolve >=0.2g/l of Al (in terms of Al2O3) at 20 deg.C within 30min in a buffer of pH12 and (B) KAlO2 and/or KOH at the weight ratio 1:(0.5 to 4). 2 to 10wt.% of the present preventive is added to cement. Thereby, the whitening will be prevented even under severe environmental conditions without losing the fluidity and initial mechanical strength of mortal or concrete.