Macro-Micro Properties of Remodeled Waste Slurry Under Freeze-Thaw Cycles

Waste slurry, a major by-product of urban construction, is produced in rapidly increasing volumes each year. Dehydrated waste slurry has potential as a roadbed material; however, its performance in freeze-thaw environments, which can induce frost heave and thaw settlement, and the mechanism of the influence of freeze-thaw cycles on its macro and micro properties are still unclear and need thorough investigation. This study explores the macroscopic and microscopic properties of waste slurry subjected to freeze-thaw cycles. We conducted unconfined compressive strength (UCS) and triaxial unconsolidated undrained (UU) shear tests, focusing on fissure compaction, elastic deformation, plastic yielding, and strain hardening stages. The results reveal a decrease in strength and elastic modulus with increasing freeze-thaw cycles, as well as in the damage degree generated by freeze-thaw cycles. To uncover the underlying microscopic mechanisms, we performed Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and mercury intrusion porosimetry (MIP) analyses. These tests highlighted the evolution of pores and microcracks during freeze-thaw cycles. These results have important reference values for the reutilization of waste slurry discharged from large-diameter bored piles for roadbed backfill materials that need to be repaired quickly in seasonally frozen areas.