Abstract: Herein, a self-made accelerated corrosion equipment is used to analyze the crystallization degree, axial and zonal compressive strength of concrete surface in different concentrations (0%, 5%, and 10%) of sodium sulfate solution at different temperatures ( 20 ℃, 40 ℃, and 60 ℃), revealing the effect of environmental thermal fatigue-sulfate erosion coupling on the mechanical properties of concrete in western saline soil areas in China. Findings are as follows: (1) Under the action of sulfate erosion, the morphology of the specimen shows crystallization and slight concrete spalling, but its mechanical properties exhibit no obvious attenuation. (2) The effect of thermal fatigue on the mechanical properties of concrete varies. The thermal fatigue at 40 ℃ improves the mechanical properties of the specimens, while the thermal fatigue at 60 ℃ significantly reduces the mechanical properties. (3) Under the coupling effect of thermal fatigue and sulfate erosion, the morphology of the specimens shows serious damages, such as serious crystallization and concrete spalling, and the mechanical properties also shows a significant attenuation. Under the coupling effect, the thermal fatigue causes the deterioration of the concrete from the early stage of the erosion, while the sulfate effect begins to accelerate the deterioration of the concrete in the late stage of the erosion. (4) Comparing the mechanical properties of the concrete adsorption zone and the immersion zone, it is found that although the two trends are the same, the attenuation of the adsorption zone is larger than that of the immersion zone. Regression analysis shows that the mechanical properties of partial concrete is highly correlated with overall concrete, and the deterioration of the concrete at the adsorption zone primarily causes the overall concrete deterioration.

Key words: western saline soil, high temperature and large temperature difference, thermal fatigue-sulfate corrosion, mechanical properties of concrete