As two of the most abundant and destructive salts in nature, sodium and magnesium sulfates can affect the physico-mechanical characteristics of stones and, thus, their durability. In this paper, the effects of these salts are compared on some physico-mechanical characteristics of travertine, including point load index (PLI), Brazilian tensile strength (BTS), P-wave velocity (Vp), and porosity (n). For this purpose, a travertine sample was obtained from the Abasabad quarry in Mahallat (central Iran) and transferred to the laboratory. Next, salt crystallization tests in sodium and magnesium sulfate solutions were carried out for up to 30 cycles. Afterward, PLI, BTS, Vp, and n of the sample were measured after every 5 cycles of the salt crystallization test. The decay constant (λ), half-time (N_1/2), and the rate of loss (RL) were used to compare the effects of sodium and magnesium sulfates on the PLI, BTS, Vp, and n of the sample. Here, λ and N_1/2 were obtained from regression curves developed between the measured PLI, BTS, Vp, and n with cycles of salt crystallization tests. The RL and N_1/2 of the PLI, BTS, Vp, and n show that the durability of the sample subjected to the salt crystallization tests in sodium and magnesium sulfates was different. The results indicate that the effect of sodium sulfate on the PLI, BTS, Vp, and n of the sample was more severe than that of magnesium sulfate. Generally, PLI, BTS, Vp, and n not only indicate visible changes occurring in the sample due to salt crystallization action (e.g., mass loss, powdering, pitting, and detachments) but also show its inner microstructural modifications due to pores development. In addition, the PLI, BTS, Vp, and n can be good indicators for preventive and monitoring purposes and suitable tools for uncovering the initial stages of building stones’ deterioration subjected to salt crystallization action. These parameters are vital when it is not possible to detect the changes in the inner structure of building stones with the naked eye.

作为自然界中含量最丰富、最具破坏性的两种盐类，硫酸钠和硫酸镁会影响宝石的物理机械特性，从而影响其耐用性。在本文中，比较了这些盐对石灰华一些物理机械特性的影响，包括点载荷指数 (PLI)、巴西抗拉强度 (BTS)、纵波速度 (Vp) 和孔隙率 (n)。为此，从 Mahallat（伊朗中部）的 Abasabad 采石场获取了石灰华样本，并将其转移到实验室。接下来，在硫酸钠和硫酸镁溶液中进行了多达 30 个循环的盐结晶测试。之后，在每 5 个盐结晶测试循环后测量样品的 PLI、BTS、Vp 和 n。衰减常数 (λ)、半衰期 ( N _1/2) 和损失率 ( RL ) 用于比较硫酸钠和硫酸镁对样品的 PLI、BTS、Vp 和 n 的影响。此处，λ 和N _1/2是从测得的 PLI、BTS、Vp 和 n 与盐结晶测试循环之间建立的回归曲线获得的。RL和N _1/2 _PLI、BTS、Vp 和 n 的值表明，在硫酸钠和硫酸镁中进行盐结晶测试的样品的耐久性不同。结果表明，硫酸钠对样品的 PLI、BTS、Vp 和 n 的影响比硫酸镁更严重。通常，PLI、BTS、Vp 和 n 不仅表示由于盐结晶作用（例如，质量损失、粉化、点蚀和分离）而在样品中发生的可见变化，而且还显示由于孔隙发展而导致的内部微观结构变化。此外，PLI、BTS、Vp 和 n 可以作为预防和监测目的的良好指标，也是揭示盐结晶作用下建筑石材劣化初始阶段的合适工具。