Abstract:The effects of Na bentonite and Ca bentonite on resistance of cementitious materials to sulfate attack at low temperature were studied. The paste samples made from cement and limestone powder were immersed in 5%(by mass) Na2S04 solution at 5℃ and the corrosion products were analyzed by IR and XRD. It is indicated that the degree of corrosion of cement limestone powder specimens aggravated with immersion time. The specimens without bentonite fell off at edges and corners notably, and thaumastie was the main component of corrosion products. In corrosion products of specimens, the content of thaumasite generation decreases with the increase of bentonite content, and the corrosion degree of specimens decreases as well. When the use level of bentonite is the same, the effect of Na bentonite to improve resistance of the cement limestone powder cementitious material to sulfate attack at low temperature is greater than that of Ca bentonite.
