Experimental study on salt weathering of sandstone with different weathering degrees

Figures & data

Figure 1. Location map of the Nanshiku Temple in Pingliang, Gansu, China.

Table 1. Analysis of rock minerals and their contents (%)

lithology	Quartz	feldspar	plagioclase	illite
Sandstone	65.4	5.2	3.1	26.3

Figure 2. Example map of the weathered state of the Nanshiku Temple, Gansu, China.

Figure 3. Diagram of freeze-thaw cycle temperature variation.

Table 2. Table of group of stone samples.

Number of cycles	0 cycles	5 cycles	10 cycles	15 cycles	20 cycles	25 cycles
C-Series Stone Samples	C1	C2	C3	C4	C5	C6
F-Series Stone Samples	F1	F2	F3	F4	F5	F6

Table 3. Indicators of sandstone with different weathering degrees.

Sample code	Open porosity φ (%)	Water absorption Wa (%)	Capillary water coefficient ω (kg·m^−2·h^−1/2)	Wave velocity ʋ (km·s^−1)	Surface hardness R/HL	Dry densityʋ ρ/(g·cm^−1)
F1、C1	6.25±0.25	2.35±0.25	1.5±0.1	2.500±0.200	670±15	2.52±0.25
F2、C2	6.35±0.15	2.40±0.20	2.0±0.1	2.450±0.150	655±10	2.48±0.20
F3、C3	6.65±0.35	2.50±0.20	2.1±0.1	2.400±0.100	625±10	2.42±0.30
F4、C4	6.70±0.30	2.55±0.25	2.3±0.2	2.300±0.100	615±15	2.37±0.25
F5、C5	6.95±0.55	2.60±0.20	2.4±0.2	2.250±0.150	610±15	2.24±0.20
F6、C6	7.50±0.50	2.75±0.25	2.5±0.2	2.150±0.150	605±20	2.12±0.25

Figure 4. Surface degradation characteristics of stone samples under salt weathering.

Figure 5. Macroscopic characteristics of salt weathering cycles of stone samples with different weathering degrees after fifteen times.

Figure 6. Microscopic morphology of stone samples under salt weathering.

Figure 7. Mass change rate curve of sample during salt weathering.

Figure 8. The measured and fitting curves of wave velocity during salt weathering.

Table 4. Variation in wave velocity values of rock samples with different degrees of weathering under salt weathering.

Number of salt cycles (n)	F1	F2	F3	F4	F5	F6
0	2.401	2.352	2.333	2.265	2.260	2.255
5	2.311	2.228	2.171	2.145	2.135	2.063
10	2.144	2.069	2.047	1.988	1.970	1.913
15	2.015	1.961	1.934	1.804	1.741	1.717

Figure 9. Surface hardness curves of samples during salt weathering.

Figure 10. Surface hardness measured and deterioration model curves.

Figure 11. Failure characteristics of F1~F6 samples under uniaxial compression after salt weathering.

Figure 12. UCS curve of sandstone under different weathering.

Figure 13. Curves for the rate of loss of UCS of stones before and after salt weathering.

Figure 14. The curves of UCS and wave velocity were compared during the experiment.

Figure 15. The curves of UCS and surface hardness were compared during the experiment.

Data availability statement

Data Sharing is not applicable.