Revealing the evolution of freeze-thaw damage in soil-rock mixtures with different moisture contents using characteristic parameters of electrochemical conductivity pathway equivalent models

Abstract

Understanding the intrinsic relationship between microstructure and macroscopic properties under freeze-thaw (F–T) cycles is of great significance for advancing knowledge of soil-rock mixtures (SRM) in low-temperature environments. This study conducted F–T cycles, electrochemical impedance spectroscopy (EIS), and uniaxial compression mechanical tests on SRM with varying moisture contents. An equivalent circuit model of conductive paths was proposed, and the microstructure was characterized using the parameters of these paths. The paper examined the effects of varying moisture contents and F–T cycles on the characteristics of conductive paths and mechanical properties, exploring the underlying mechanisms. The results indicated that the increasing moisture content enlarged the cross-sectional area of CP and DSRP and enhanced the double-layer effect, while simultaneously reducing the ion concentration within DSRP. F–T cycling induced pore expansion and interconnection, resulting in increased contact areas and shortened lengths of CPP and CP, as well as increased contact areas and numbers of DSRP. The uniaxial strength degradation model based on ΔC_DSRP(t) can be used to evaluate the peak strength after different cycles. Under F–T cycling, the expansion of DSRP exerted a deleterious effect on peak strength. Water – ice phase transitions increased the contact area of soil – rock cemented interfaces of DSRP and enhanced the double-layer effect.

Keywords

soil-rock mixture / moisture content / electrochemical impedance spectrometry / microscopic structure / mechanical properties / deterioration model

References

[1] Liu J-x, Sun S-r, Wei J-h, et al.. Physical and mechanical properties of root-reinforced soil–rock mixture investigated by CT scanning and direct shear tests [J]. Catena, 2026, 268: 110046

[2] Qiu P-y, Tang L-y, Wang P-y, et al.. A creep model for soil-rock mixture considering the effect of rock contents and freeze-thaw cycles [J]. Engineering Geology, 2024, 333: 107496

[3] Ning R-h, Wang Z-p, Peng J-b, et al.. Multi-scale structure deterioration mechanisms of the Cenozoic red-bed mudstone under freeze-thaw cycles in the guide Basin, Northeastern Tibetan Plateau [J]. Bulletin of Engineering Geology and the Environment, 2026, 85(4): 180

[4] Wei J-h, Hu S-l, Deng Z-d, et al.. Experimental study on macro-meso damage of jointed rock mass under sequential cyclic loading–unloading followed by freeze - thaw cycles [J]. Transportation Geotechnics, 2026, 58: 101929

[5] Yu S-t, Deng H-w, Tian G-l, et al.. Research on dynamic compressive characteristics of rocklike material considering the influence of crack angles and freeze - thaw cycles [J]. Arabian Journal of Geosciences, 2022, 15(6): 482

[6] Gao F, Xiong X, Xu C-s, et al.. Mechanical property deterioration characteristics and a new constitutive model for rocks subjected to freeze-thaw weathering process [J]. International Journal of Rock Mechanics and Mining Sciences, 2021, 140: 104642

[7] Yang Z-y, Xu Y, Yu M-l, et al.. Failure mechanism of unsaturated sandstone under freeze-thaw cycles: Critical saturation effect and segmented damage modeling [J]. Engineering Fracture Mechanics, 2026, 335: 111902

[8] Xiong X, Zhou K-p, Gao F, et al.. A new damage constitutive model for frozen-thawed sandstone under triaxial conditions: Considering the characteristics of pre-peak compaction and post-peak residual strength [J]. International Journal of Damage Mechanics, 2024, 33(3): 193-222

[9] Xiong X, Gao F, Zhou K-p, et al.. Dynamic tensile mechanical properties of water-saturated and frozen sandstone after freeze-thaw fatigue damage treatment [J]. Journal of Materials Research and Technology, 2023, 24: 9323-9338

[10] Tian G-l, Deng H-w, Zhao B-k, et al.. A study on the evolution of microstructure of soil-rock mixtures based on the electrochemical conductive paths model under different rock and moisture content conditions [J]. International Journal of Pavement Engineering, 2024, 25(1): 2371451

[11] Gunupuram J P, Kumar R, Deb D. Determination of shear strength parameters of in-situ soil rock mixtures using large scale shear apparatus and comparison with laboratory tested samples [J]. Engineering Geology, 2025, 352: 108060

[12] Dai M, Wang K-c, Xiao J-h, et al.. Compaction and shear behavior of red-stratum mudstone soil-rock mixture with different rock content [J]. Bulletin of Engineering Geology and the Environment, 2025, 84(11): 529

[13] Tang L-y, Wang X, Qiu P-y, et al.. Study on shear performance of soil-rock mixture at the freezing-thawing interface in permafrost regions [J]. Rock and Soil Mechanics, 2020, 41(10): 3225-3235(in Chinese)

[14] Zhou Z, Li F, Yang H, et al.. Orthogonal experimental study of soil - rock mixtures under the freeze - thaw cycle environment [J]. International Journal of Pavement Engineering, 2021, 22(11): 1376-1388

[15] Xing K, Zhou Z, Yang H, et al.. Macro - meso freeze - thaw damage mechanism of soil - rock mixtures with different rock contents [J]. International Journal of Pavement Engineering, 2020, 21(1): 9-19

[16] Tang L-y, Shao H-t, Tan X-j, et al.. A review of the strength deterioration mechanism of soil-rock mixtures in cold regions [J]. Cold Regions Science and Technology, 2026, 248: 104953

[17] Tang L-y, Li G, Luo T, et al.. Mechanism of shear strength deterioration of soil-rock mixture after freeze - thaw cycles [J]. Cold Regions Science and Technology, 2022, 200: 103585

[18] Tang L-y, Lu Z-h, Zheng J-j, et al.. Mechanism of strength degradation of frozen soil - rock mixture under temperature rise-induced particle ice film ablation [J]. Permafrost and Periglacial Processes, 2023, 34(4): 530-546

[19] Qiu P-y, Tang L-y, Zheng J-g, et al.. Experimental investigations on the shear strength and creep properties of soil-rock mixture under freeze-thaw cycles [J]. Cold Regions Science and Technology, 2024, 217: 104037

[20] Tang L-y, Li G, Li Z, et al.. Shear properties and pore structure characteristics of soil - rock mixture under freeze - thaw cycles [J]. Bulletin of Engineering Geology and the Environment, 2021, 80(4): 3233-3249

[21] Tang L-y, Lu Z-h, Zhao T, et al.. Exploring strength deterioration mechanism of soil-rock mixture based on pore structure characteristics under freeze - thaw cycles [J]. Cold Regions Science and Technology, 2024, 217: 104040

[22] Song G-ling. Equivalent circuit model for AC electrochemical impedance spectroscopy of concrete [J]. Cement and Concrete Research, 2000, 30(11): 1723-1730

[23] Ke R, Wang L-q, Zou Z-x, et al.. An analytical model for anchor-mortar interface bonding based on electrochemical impedance spectroscopy [J]. Cement and Concrete Composites, 2023, 142: 105196

[24] Han P-j, Zhang Y-f, Chen F Y, et al.. Interpretation of electrochemical impedance spectroscopy (EIS) circuit model for soils [J]. Journal of Central South University, 2015, 22(11): 4318-4328

[25] Dong H, Chen L, Jiang X-z, et al.. Study on the characteristics of the soil-rock mixture structure based on the high-frequency extremum of the electrochemical impedance spectroscopy [J]. Chinese Journal of Rock Mechanics and Engineering, 2017, 36(S2): 4134-4141

[26] Dong H, Zhu X-m, Chen L, et al.. Study on pore characteristics of soil-rock mixture resistance similarity based on the electrochemical impedance spectroscopy [J]. Chinese Journal of Scientific Instrument, 2020, 41(11): 119-128(in Chinese)

[27] Dong H, Zhu X-m, Jiang X-z, et al.. Structural characteristics of soil-rock mixtures based on electrochemical impedance spectroscopy [J]. Catena, 2021, 207: 105579

[28] Xu W-j, Zhang H-yang. Meso and macroscale mechanical behaviors of soil - rock mixtures [J]. Acta Geotechnica, 2022, 17(9): 3765-3782

[29] Lindquist E S, Goodman R E. Strength and deformation properties of a physical model melange [C]. Proceedings of the 1st North American Rock Mechanics Symposium (NARMS), 1994, Rotterdam, A.A. Balkema843-850

[30] Medley E, Lindquist E S. The engineering significance of the scale-independence of some Franciscan melanges in California, USA [M]. Rock Mechanics, 2026, London, CRC Press907914

[31] GB/T 50123-2019 Geotechnical Test Method Standard, Ministry of Water Resources of the People’s Republic of China [S]. (in Chinese)

[32] GB/T 50266-2013 Standard for test methods of engineering rock mass, Ministry of Housing and Urban-Rural Development of the People’s Republic of China [S]. (in Chinese)

[33] JTG E41—2005 Test methods of rock for highway engineering, Ministry of Transport of the People’s Republic of China[S].(in Chinese)

[34] SL/T 264—2020 Code for rock tests in water and hydropower projects, Ministry of Water Resources of the People’s Republic of China[S].(in Chinese)

[35] GB/T 50082-2009 Standard for test methods of long-term performance and durability of ordinary concrete, Ministry of Housing and Urban-Rural Development of the People’s Republic of China[S]. (in Chinese)

[36] Tian G-l, Deng H-w, Zhao B-k, et al.. A study of uniaxial compressive strength degradation model of soil-rock mixtures under freeze-thaw deterioration based on equivalent model characteristics of conductive paths [J]. Construction and Building Materials, 2024, 437: 136975

[37] Gu P, Xie P, Beaudoin J J. Microstructural characterization of the transition zone in cement systems by means of A. C. Impedance spectroscopy [J]. Cement and Concrete Research, 1993, 23(3): 581-591

[38] Gu P, Xie P, Beaudoin J J, et al.. A. C. impedance spectroscopy (I): A new equivalent circuit model for hydrated Portland cement paste [J]. Cement and Concrete Research, 1992, 22(5): 833-840

[39] Chighladze G, Kaleita A, Birrell S. Sensitivity of capacitance soil moisture sensors to nitrate ions in soil solution [J]. Soil Science Society of America Journal, 2010, 74(6): 1987-1995

[40] Peng Y-y, Cao Y, Chen Y-ming. The impedance magnitude of material around root affects the validity of the electrical capacitance method [J]. Acta Agrestia Sinica, 2017, 25(5): 1145-1151(in Chinese)

[41] Mitchell J K, Soga K. Fundamentals of Soil Behavior [M], 20053rd ed.New York, Wiley

[42] Baker R, Frydman S. Unsaturated soil mechanics: Critical review of physical foundations [J]. Engineering Geology, 2009, 106(1–2): 26-39

RIGHTS & PERMISSIONS

Central South University

Just Accepted

This article has successfully passed peer review and final editorial review, and will soon enter typesetting, proofreading and other publishing processes. The currently displayed version is the accepted final manuscript. The officially published version will be updated with format, DOI and citation information upon launch. We recommend that you pay attention to subsequent journal notifications and preferentially cite the officially published version. Thank you for your support and cooperation.