Study on the Corrosion and Deterioration of Limestone under Long-Term Immersion of Chemical Solution

Limestone immersion corrosion test was carried out in acid (pH = 3), neutral (pH = 7) and alkaline (pH = 11) solution environments. The uniaxial compressive strength, the micro morphology of dissolved limestone surface, the pH values and Ca²⁺ concentration of immersion solution were tested to discuss the deterioration mechanism of limestone. The results showed that the dissolution deterioration degree of limestone was the largest in acidic environment, followed by neutral environment and the smallest in alkaline environment. At the beginning of the test, the pH values of the three chemical solutions changed sharply, then gradually turned to neutral, and finally became weak alkaline. In the acid solution, the dissolution rate of Ca²⁺ was faster in the initial stage. In neutral and alkaline environment, the dissolution reaction was slow. With the increase of immersion time, the micro morphology of dissolved limestone showed the expansion of micro pores and the aggravation of surface roughness. According to the statistical results of micro damage area of limestone after dissolution, the uniaxial compressive strength of limestone decreased with the increase of damage area ratio in the three immersion solutions. The damage area ratio was the largest in acid environment, followed by neutral environment and the smallest in alkaline environment.