Frost resistance and improvement techniques of recycled concrete: a comprehensive review

作者：Quan Ma, Zhenhua Duan, Jun Wang, G. George Yin, Li Xi · 发表于：Frontiers in Materials · 年份：2024 · DOI：10.3389/fmats.2024.1493191 · 被引用次数：17 · 研究领域：Recycled Aggregate Concrete Performance、Innovative concrete reinforcement materials、Innovations in Concrete and Construction Materials

In the pursuit of sustainable construction practices, the utilization of recycled concrete has emerged as a pivotal strategy, distinguished by its commitment to resource conservation and environmental stewardship. Nevertheless, the inherent micro-porosity and micro-cracking within the old mortar of recycled concrete may lead to weak bonding performance at the interfacial transition zone, culminating in diminished strength, reduced density, and elevated water absorption rates compared to conventional concrete, which critically impairs its performance in cold climates subjected to freeze-thaw cycles. Consequently, this paper provides a structured examination of the frost resistance properties of recycled concrete subjected to freeze-thaw cycling. Initially, the study delineates the mechanisms of frost-induced damage in recycled concrete by synthesizing the degradation pathways observed in both conventional and recycled concrete during freeze-thaw exposure. Subsequently, a detailed analysis is conducted to identify the pivotal factors affecting frost resistance, encompassing the proportion and moisture affinity of recycled aggregates, the addition of silica fume and fly ash, the water-to-cement ratio, and the degree of water saturation. In the final segment, the study compiles and reviews the strategies for bolstering the frost resistance of recycled concrete, including the incorporation of air-entraining admixtures, fiber reinforcement, and aggregate modification approaches. Th...