Slaking behavior of tuffs under cyclic wetting-drying conditions in aqueous solutions of different pH values

Disintegration of rock caused by wetting-drying cycles seriously threatens the long-term stability of rock mass. To investigate the slaking behavior of rocks, wetting-drying cycle slaking tests were carried out on two types of tuffs with aqueous solutions considering the initial pH values of 2, 7, and 12. The disintegration processes of the rock samples were observed, and the variation trends of the particle distributions of slaked materials were analyzed. The results show significant differences in the slaking durability between the two types of tuffs with different mineralogical compositions. The pH values of the aqueous solutions have influences on slaking characteristics for the same tuff sample. Clay minerals such as montmorillonite are the main factors for rock disintegration. In addition, the microstructure of rocks is also a factor affecting slaking durability. Water-rock chemical reaction occurs during the wetting procedure of each wetting-drying cycle. The tuff samples, which are more strongly influenced by the water-rock reaction in solution with a low pH value, are more prone to disintegrate.