(1. Bridge Engineering National Local Joint Engineering Laboratory of Disaster Prevention and Control Technology,Lanzhou Jiaotong University, Lanzhou 730070, China)（2. Key Laboratory of Road and Bridge and Underground Engineering of Gansu Province,Lanzhou Jiaotong University, Lanzhou 730070, China)
The effects of different water-cement ratio cement mortar on the sulfate resistance under full immersion were studied. Ordinary Portland cement, high 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 days, compressive strength and relative elastic modulus were examined. Concrete samples were fully immersed in 3wt% Na2SO4 sulfate solution at （20±2）℃, and their strength and elastic modulus were measured. Then the corrosion resistance of the concrete under full immersion was evaluated. The results show that under the condition of full immersion, the corrosion resistance of 0.36 water-cement ratio is lower than that of 0.32 water-cement sample, and the resistance to sulfate attack increases with the decrease of water-cement ratio. Concrete was mixed with mineral powder-silica fume after full immersion conditions to enhance the performance of sulfate erosion significantly. High sulfur-resistant cement can improve the performance of concrete sulfate attack by limiting the content of C3A, which is not necessarily applicable in any environment. The resistance coefficient and relative elastic modulus of low-water-cement concrete and concrete mixed with mineral powder-silica are higher, which is confirmed by connected porosity, further showing low-water-cement concrete mixed with mineral powder-silica can significantly improve the performance of concrete resistance to sulfate attack.