2026-10-11T21:28:10Z https://www.scidb.cn/oai

10.57760/sciencedb.40624 2026-07-01T18:25:05Z

2026-07-01 Engineering Property of Salt-Contaminated Clay: Mechanistic Insights from Diffuse Double Layer Evolution and Salt Crystallization Effect with Liquid Limit Prediction doi:10.57760/sciencedb.40624 en Salt contamination can substantially alter the engineering properties of natural clay, but liquid limit responses vary markedly with salt type and concentration. The physicochemical mechanisms governing these differences and their quantitative relationships with liquid limit evolution remain unclear. In this study, natural clay was treated with three representative sodium salts: Na2SO4, NaHCO3, and NaCl. pH and electrical conductivity measurements, Atterberg limit tests, and sedimentation tests were conducted, together with particle size distribution, X-ray diffraction, environmental scanning electron microscopy, and zeta potential analyses. A 9-day equilibrium period was identified through water-salt equilibrium tests. With increasing salt concentration, the three groups exhibited distinct liquid limit evolutions governed primarily by diffuse double layer (DDL) evolution and salt crystallization effect. In the Na2SO4 group, the liquid limit first decreased and then increased near the crystallization threshold. DDL compression dominated below the threshold, whereas crystal precipitation subsequently altered pore structure, particle contacts, and water binding. In the NaHCO3 group, the liquid limit increased and then stabilized because alkaline hydrolysis and deprotonation promoted DDL expansion and particle dispersion, whereas subsequent crystallization restricted further expansion. In the NaCl group, the liquid limit generally decreased because increasing ionic strength compressed the DDL and promoted particle flocculation. Salt-specific semi-empirical prediction models were further developed using DDL evolution and salt crystallization effect as the primary controlling factors, achieving R² values above 0.96. Overall, this study elucidates the physicochemical mechanisms governing salt-dependent liquid limit evolution and provides a practical approach for predicting the liquid limit of salt-contaminated clay. Salt-contaminated clay; engineering property; diffuse double layer (DDL); salt crystallization; prediction model ze gong PUBLIC https://creativecommons.org/licenses/by/4.0/ dataset Science Data Bank