Evaluation of Frost Resistance of Stone Materials in De-icing Salt Solutions

Due to the fact that no standard method for testing the frost resistance of stone materials in the presence of deicing salts has been developed so far, a new method is proposed in this article. The test method was based on the PN EN 12371 and PKN-CEN /TS 12390-9 standards and consisted of freezing to -12OC and thawing samples in salt solutions. Three criteria were used to assess the impact of the cycles: visual assessment, change in mass, and change in compressive strength. Nine different stone materials were selected, samples of which were subjected to frost resistance testing in salt solutions with concentrations of 3% sodium chloride (NaCl), 25% NaCl, and 30% calcium chloride (CaCl2). The impact of chlorides on the stone material was significant, causing, among other changes, a decrease in compressive strength, damage to the samples, the appearance of salt efflorescence, and a change in color. The greatest reduction in strength was noted for sandstones (from about 20% to over 40%). On the other hand, the most resistant were black gabbro samples (reduction in compressive strength from 2% to 7%). Comparing the solutions, the greatest reduction in the strength of the materials was obtained after cyclic freezing and thawing in a 25% NaCl solution, amounting to a 22% reduction on average. On the other hand, the compressive strength of samples subjected to frost resistance testing in other salt solutions decreased on average by 18%, and for frost resistance in water by 10%.