Variations in capillary water absorption and porosity of some limestones during weathering due to salt and air pollutants

As a building material, limestone is affected salt and acid solutions resulting from intense weather conditions over time. In the present study, variations in capillary water absorption, porosity, physical changes, and internal rock decomposition mechanisms caused by salt crystallization and air pollutants (SO x and NO x ) in sedimentary limestone from the Antalya region were explored. The mineralogical–petrographical and geochemical properties of the limestones were determined using polarizing light microscopy, scanning electron microscopy (SEM), and X-ray fluorescence methods. The variations in the capillary water absorption coefficient, weight, and pore distribution and size were also determined by mercury porosimetry (MIP). An increase in weight was observed in the salt and SA (150 ± 10 mL deionized water and 500 ± 10 mL H 2 SO 3 acid) weathering tests, but a reduction in weight was found under the action of NA (150 ± 10 mL deionized water and 500 ± 10 mL HNO 3 acid). The reaction of SA with the limestones influenced the presence of calcium sulphite hemihydrate and gypsum on the rock surface, which affected weight gain. A decrease was observed in the weights of the limestones under the action of NA, and the porous structure seen in the microscale examination from SEM analysis supported a loss of material. The values for capillary water absorption increased in the limestones exposed to salt, SA, and NA. According to MIP analysis, the pore size distribution curves became multimodal, and the pore sizes varied in the studied limestones exposed to salt, SA, and NA. The findings of our study serve as an important guide for the use of limestone as a natural stone in regions with severe weather conditions.