Study on freeze–thaw cyclic durability of reclaimed ceramic concrete in western high altitude region

To achieve the resource utilization of waste ceramic particles and promote the application of recycled concrete in cold regions, this study systematically investigates the effects of waste ceramic particle replacement ratios on the freeze-thaw resistance and service reliability of recycled concrete. Six groups of specimens with ceramic particle replacement ratios of 0%, 20%, 40%, 60%, 80%, and 100% were designed. Freeze-thaw cycle tests were carried out using the rapid freezing method, with mass loss rate and relative dynamic elastic modulus as the key evaluation indicators to determine the optimal mix proportion. Scanning electron microscopy (SEM) was used to observe the evolution of the microstructure, and a reliability function was established based on the Wiener distribution probability model to predict the remaining service life of the optimally proportioned specimens. The results show that during freeze-thaw cycles, the relative dynamic elastic modulus of all specimens decreases continuously, while the mass loss rate exhibits a variation trend of initial increase followed by subsequent decrease. The specimens with a 20% ceramic particle replacement ratio demonstrate the best freeze-thaw resistance, failing only after 398 freeze-thaw cycles. Microstructural analysis reveals that at early freeze-thaw cycles, the damage is dominated by the deterioration of the surface interfacial transition zone (ITZ), whereas at high cycles, severe degradation occurs, including pore connectivity and the collapse of the cementitious network formed by hydration products. When the ceramic particle replacement ratio exceeds 20%, the freeze-thaw resistance of the specimens decreases significantly. This study reveals the freeze-thaw deterioration mechanism of recycled concrete incorporating waste ceramic particles as aggregates, and the findings provide a theoretical basis and technical support for the mix optimization and engineering application of such recycled concrete in cold regions.