## 2 Experimental Design
### Experimental Methods  
To replicate the real weathering conditions experienced by stone artifacts, the experimental setup was designed to mimic the climatic conditions of their respective locations. The summer climates of Leshan and Huai'an share similar characteristics, with average temperatures ranging from 30 to 35 \({}^{\circ}\)C and relative humidity ranging from 40% to 70%. These conditions served as the basis for conducting accelerated salt weathering simulation tests. The simulation tests for sulfate weathering primarily involved a \"soaking-resting\" cycle. The specific steps were as follows. (1) The test samples were immersed in a saturated sodium sulfate solution for 24 h, after which they were removed, and the surface suspension was wiped off using a damp cloth. (2) The rock samples were then placed in a rapid temperature and humidity test chamber (Huanrui: RHPS-408 BT, Dongguan, China) for 48 h, with the temperature and humidity set at 35 \({}^{\circ}\)C and 45%, respectively, to simulate the cyclic effects of salt weathering. This process was repeated continuously. Each cycle of sulfate weathering lasted for 72 h. Figure 2 illustrates some of the operational procedures.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Rock Type** & \begin{tabular}{c} **Dry Density** \\ **\(r_{d}\)/g: cm\({}^{-3}\)** \\ \end{tabular} & \begin{tabular}{c} **Water** \\ **Absorption** \\ **\(\omega\)/\%** \\ \end{tabular} & \begin{tabular}{c} **Total** \\ **Porosity** \\ **\(q\)/\%** \\ \end{tabular} & \begin{tabular}{c} **Leeb Hardness** \\ **R/HL** \\ **\end{tabular} & \
\begin{tabular}{c} **Wave** \\ **Velocity** \\ \(u\)/s:m\({}^{-1}\)** \\ \end{tabular} &
\begin{tabular}{c} **Uniaxial Compressive** \\ **Strength** \\ **_UCS/MPa** \\ \end{tabular} \\ \hline Sandstone & \(2.25^{+0.21}_{-0.12}\) & \(2.68^{+0.17}_{-0.24}\) & \(7.59^{+0.27}_{-0.36}\) & \(632^{+16}_{-25}\) & \(2400^{+350}_{-200}\) & \(77.85^{+7.96}_{-5.85}\) \\ Limestone & \(2.69^{+0.16}_{-0.11}\) & \(0.17^{+0.08}_{-0.03}\) & \(0.68^{+0.18}_{-0.21}\) & \(685^{+10}_{-15}\) & \(3400^{+300}_{-250}\) & \(140.25^{+6.45}_{-10.25}\) \\ \hline \hline \end{tabular}
\end{table}
Table 1: Basic physical parameters of fresh sandstone and limestone.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Mineral Composition** & **Quartz** & **Albite** & **Microline** & **Calcite** & **Clay Minerals** \\ \hline Relative content (\%) & 46–55 & 18–25 & 7–12 & 13–19 & 3–7 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Relative contents of fresh sandstone.  
The samples were divided into six groups, each containing five pieces, meaning a total of thirty pieces of sandstone and thirty pieces of limestone.  
The number of cycles was set to 0, 5, 10, 15, 20 and 25, and the whole testing process lasted about 90 days. In other words, the sample that underwent the first cycle of salt weathering was subjected to a total of 25 cycles. The samples that were not subjected to any weathering tests are considered fresh rock samples. A set of sandstone and limestone samples were subjected to testing at intervals of five cycles. At the conclusion of the test, the weathering indices of the two rocks were determined separately, along with an analysis of their mineral composition and pore size distribution. Finally, a uniaxial compression test was conducted.