Influence of Sulfate Attack and Drying-Wetting Cycle on Properties of Mortar

This paper presents the study on mortar specimens exposed to three kinds of Na2SO4 solution(0.5%,5%and10%)and different drying-wetting cycles(20,30,40and75). Influence of cycle number and solution concentration on mechanical behavior, mass and appearance of mortar specimen was analysis. The results show that surface of specimen in 5% and 10% solution shows obvious desizing, sandiness and some crack at 75 drying-wetting cycles. In different solution concentration, mass of specimen shows a trend to increase firstly then decrease lately. The increasing and declining separately of specimen mass are more obvious in high concentration solution. In three kinds concentration of solution, peak stress and modulus of elasticity of specimen show the same trend to increase in early erosion stage and decrease in late erosion stage. Change rate of mechanical behavior of specimen in high concentration solution is larger than that of in low concentration solution at early and later stage separately. On the contrary, peak strain show a trend to decline firstly then increase lately.