Abstract: The solution used in this study contained mainly SO^2-₄， Cl^-， and Mg²⁺ ions， which closely resembled the chemical corrosion environment in the factories. Concrete degradation was investigated by conducting on-site exposure tests and indoor simulation tests， studying the influences of different soaking method， water binder mass ratio， solution mass fraction， and dry-wet cycle on concrete degradation. Ultrasonic wave detection was used to analyze the degree of concrete degradation. The results showed that the thickness of concrete damaged layer increased due to the reaction， however， the growth rate decreased gradually under the multi-salt coupling corrosion. In the early stage of corrosion， Cl^- and SO^2-₄ entered the concrete and reacted with each other， causing a greater concentration difference between the inside and outside of concrete， which accelerated the invasion of corrosion ion and the corrosion rate. In the middle and late stage of corrosion， Mg²⁺ and SO^2-₄ participated in the corrosion， leading to increased defects. As the corrosion progressed， the concentration difference decreased， and the corrosion rate slowed down. Based on the experimental results， a damage development model was proposed， and it was concluded that the indoor simulation test corrosion of 1.37d was equivalent to the on-site semi-immersion test corrosion of 1d， with relatively accurate results.

Key words: concrete; chemical corrosion; ultrasonic testing; field exposure test; laboratory simulation test