关键词: 硫酸盐侵蚀;抗压侵蚀系数;相对动弹性模量;含气量;连通孔隙率;相关性

Abstract: The effects of different water-cement ratio cement mortar on the sulfate resistance under full immersion were studied.Ordinary Portland cement, medium sulfur-resistant cement and slag with silica fume cement concrete samples were prepared with water-cement ratio of 0.32 and 0.36.After standard curing for 28 d, the compressive erosion coefficient and relative elastic modulus of the specimen were measured in the 3%Na2SO4solution at(20 ±2)℃, the concrete air content and connected porosity measured after 240 d erosion,and the resistance to sulfate attack of concrete was evaluated at(20 ±2)℃.The results show that,under the effect of(20 ±2)℃full immersion,(1)the resistance to sulfate attack of concrete is E>A>B,and the medium sulfur-resistant cement mainly limit the content of C 3A to improve the resistance to sulfate attack of concrete, which may not work in any environment;(2)The corrosion resistance of 0.36 water-cement ratio is lower than that of 0.32 water-cement ratio, and the resistance to sulfate attack increases with the decrease of water-cement ratio;(3)Low water-cement ratio concrete mixed with mineral powder-silica fume after full immersion conditions to enhance the resistance of sulfate erosion significantly;(4)The resistance coefficient of concrete and its relative elastic modulus is highly correlated.After 240 d of erosion, the air content and connected porosity of the different mix ratio concrete are very close to each other,and the correlation coefficient is 0.93, so it is reasonable to choose test evaluation index,reducing the waste of raw materials and testing work.

Key words: sulfate attack;resistance coefficient;relative elastic modulus;air content;connected porosity;correlation