Degradation of limestone used as building materials under the influence of H2SO3 and HNO3 acids.

Air pollution is one of the most complex atmospheric conditions and causes the deterioration of the natural stone. Air pollutants are effective on the deterioration process of natural stones, and this process varies in wet and dry environmental conditions. In this study, the ageing resistance to H₂SO₃ (SSA) and HNO₃ (NSA) solutions in the presence of moisture of four limestone samples from the Elmalı region were analyzed based on standard procedures. The mineralogical-petrographic features and pore size distribution were also determined using a polarized light microscope (PLM), scanning electron microscope (SEM–EDX), and high-pressure mercury porosimetry (MIP). Physical and morphological (weight, roughness, color and microtextural properties) variations were also observed in the studied samples after SSA and NSA treatments. Secondary gypsum with different crystal morphology was observed on the surfaces of calcite crystals under the influence of SSA. The NSA treatment caused the emergence of secondary pores. The weight, whiteness and roughness increased with the effect of SSA in the presence of moisture. The weight and whiteness decreased and the roughness increased after NSA exposure. [ABSTRACT FROM AUTHOR]