Effects of dry–wet cycles on the dynamic characteristics of cement-stabilized loess

Abstract

Cement-stabilized loess is widely employed for subgrade construction in the loess region of China, and its long-term stability performance is threatened by dry‒wet (D‒W) cycles that result from climate change. Examining the dynamic characteristics of cement-stabilized soil subjected to D‒W cycles is imperative. This study investigated the dynamic characteristics (including accumulated plastic deformation and dynamic resilient modulus) of cement-stabilized loess under various cement contents and numbers of dry‒wet cycles (D‒W = 0, 1, 3, 5, and 7) via dynamic triaxial tests. The micromechanisms were revealed through Scanning Electron Microscopy (SEM) analysis. The key findings are summarized as follows: (1) Cement addition (3–9%) significantly improved the deformation resistance and dynamic resilient modulus (increased by 99.7–148.6%) via hydration-driven microstructural densification and interparticle bond reinforcement. The deformation mechanism shifts from moisture-driven destructive linear growth in natural loess to cementation-controlled asymptotic stabilization under cyclic loading. (2) D‒W cycles induce different deterioration effects. The natural loess exhibited a 99% increase in accumulated plastic deformation after 7 cycles, whereas the cement-stabilized loess exhibited reduced growth rates (65%, 50%, and 30% for C = 3%, 6%, and 9%, respectively). A high cement content (C = 9%) achieved asymptotic stabilization by prioritizing cementation over moisture sensitivity via pore refinement and interfacial bond reinforcement. (3) A proposed empirical formula for the dynamic resilient modulus effectively predicts D‒W cycle-induced degradation trends. Validation against test data and other literature confirmed its universality and accuracy.