Effect of Mineral Fillers on Sulfate Resistance of Portland Cement Mortars
SourceSulfate-resisting properties of cement mortars containing ground lime-stone, dolomite, and basalt were studied from the expansion and deterioration of 25.4 by 25.4 by 158.8 mm prisms immersed in 5 percent (Na2SO4) solution for up to 11 months. Fillers content varied from 10 to 40 percent of the cement by weight, and their fineness (Blaine) from 1150 to 11 000 cm2/g. The rate of expansion of the specimens containing the limestone filler was slower than that of the specimens containing the other fillers, with onset of cracking occurring in the former after 10 to 12 weeks as against 6 weeks in the latter, including the reference specimens. After 5 months, the beneficial effect of the limestone filler was only slightly evident. It seems that the addition of limestone filler improves sulfate-resisting properties of cement mortars to a limited extent only.