Experimental study on carbonate dissolution and erosion effect under attack of simulated sulphuric acid rain

The carbonate rocks are known to suffer from attack of acid rain due to high content of soluble minerals. In order to simulate the process of deterioration of carbonate rocks, the attack of acid rain on different carbonate specimens is accelerated by increasing the acid strength and rainfall intensity. Under simulated sulphuric acid rain, the variations in Ca²⁺ concentration, pH value variation, H⁺ consumption rate of the solution as well as the mass loss are tested. The dissolution mechanism is analyzed and discussed based on the experimental results. Also, the pore characteristics are investigated and analyzed for impact on dissolution process. The results indicate that the dissolution products are removed from rock surface. This leads to mass loss and accelerated removal of the specimens and subsequently changes in micro structures. However, during the dissolution process, parts of micro pores and structures (<0.01 μm) are filled by gypsum crystal, and this can protect the micro pores from further damage. Thus, the porosity and pore characteristics have great influence on the dissolution process. Higher porosity and larger-sized pores are more conducive to the dissolution effect and further erosion. The conclusion may be taken as the scientific support for weathering researches on carbonate rocks and protection of carbonate stone relics.