Sodium sulfate, as a commonly used early strengthening agent, has been widely used in different areas. Because of its sulfonic acid group, sodium sulfate is also used as a cement capillary crystal waterproof material. However, temperature has a significant effect on concrete mixed with sodium sulfate. The effect of sodium sulfate on the early hydration rate at different temperatures was studied by conducting a time and hydration thermal analysis. The effects of sodium sulfate on the mechanical properties of concrete at different temperatures were studied through compressive strength experiments. Impermeability at different temperatures was studied by testing resistance to chloride ion penetration and resistance to water penetration. The effect of resistance to sulfate attack was also experimentally. The hydration products were analyzed by electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The experimental results showed that at low temperature, sodium sulfate can accelerate the early hydration reaction rate, and the effect becomes weaker with increasing temperature. At low temperature, the addition of sodium sulfate can effectively improve the degree of hydration, and enhance the permeability resistance and ion erosion resistance of the matrix.

Abstract
1. Introduction
2. Material Preparation and Method
    2.1. Experimental materials
    2.2. Experimental methods and procedures
3. Results and Discussion
    3.1. Setting time at different temperatures
    3.2. Compressive strength of concrete and mortarat different temperatures
    3.3 Thermal analysis of hydration
    3.4 Chloride ion diffusion test
    3.5 Sulfate resistance test
    3.6 Scanning electron microscope
    3.7 Potential limitations or challenges
4. Conclusion
Acknowledgement
References
Author Information

• Hao Li(Anhui Province Engineering Laboratory of Advanced Building Materials, Anhui Jianzhu University, Hefei, Anhui 230601, China, Anhui Province Key Laboratory of Advanced Building Materials, Anhui Jianzhu University, Hefei, Anhui 230601, China)
• Qian Wang(Anhui Province Engineering Laboratory of Advanced Building Materials, Anhui Jianzhu University, Hefei, Anhui 230601, China, Anhui Province Key Laboratory of Advanced Building Materials, Anhui Jianzhu University, Hefei, Anhui 230601, China)
• Zilong Wu(Anhui Province Engineering Laboratory of Advanced Building Materials, Anhui Jianzhu University, Hefei, Anhui 230601, China, Anhui Province Key Laboratory of Advanced Building Materials, Anhui Jianzhu University, Hefei, Anhui 230601, China)
• Qinglin Huang(Anhui Province Engineering Laboratory of Advanced Building Materials, Anhui Jianzhu University, Hefei, Anhui 230601, China, Anhui Province Key Laboratory of Advanced Building Materials, Anhui Jianzhu University, Hefei, Anhui 230601, China)
• Qifang Ren(Anhui Province Engineering Laboratory of Advanced Building Materials, Anhui Jianzhu University, Hefei, Anhui 230601, China, Anhui Province Key Laboratory of Advanced Building Materials, Anhui Jianzhu University, Hefei, Anhui 230601, China, Key Laboratory of Huizhou Architecture in Anhui Province, Anhui Jianzhu University, Hefei, Anhui 230601, China) Corresponding author
• Yi Ding(Anhui Province Key Laboratory of Advanced Building Materials, Anhui Jianzhu University, Hefei, Anhui 230601, China)
• Haixia Ji(Anhui Province Key Laboratory of Advanced Building Materials, Anhui Jianzhu University, Hefei, Anhui 230601, China)
• Wei Xu(Anhui Lencaqi Building Materials Co., Ltd., Hefei, 230088, China)
• Yanyan Wang(School of Civil Engineering, Anhui Jianzhu University, Hefei 230601, Anhui, China)
• Kai Huang(Anhui Province Engineering Laboratory of Advanced Building Materials, Anhui Jianzhu University, Hefei, Anhui 230601, China)
• Won-Chun Oh(Department of Advanced Materials Science and Engineering, Hanseo University, Seosan 31962, Republic of Korea) Corresponding author