Effect of Recycled Ceramic Fine Aggregate (RCFA) on Strength and Durability of Concrete with Varying Water-To-Binder Ratios

To promote the effective recycling of waste ceramic tiles and alleviate the shortage of natural river sand, this study systematically investigates the strength and durability of concrete incorporating recycled ceramic fine aggregate (RCFA), herein referred to as RCFA concrete, at water-to-binder (W/B) ratios ranging from 0.25 to 0.45. The RCFA was produced by crushing waste ceramic tiles characterized by low water absorption. As indicated by experimental results, RCFA concrete exhibits improved compressive strength and enhanced resistance to freeze–thaw cycles and chloride ion penetration compared to natural aggregate concrete. However, the beneficial effects of RCFA diminish at lower W/B ratios. Furthermore, the incorporation of RCFA significantly reduces autogenous shrinkage and alleviates the decline in internal relative humidity, with these effects being more pronounced at lower W/B ratios. Conversely, RCFA increases drying shrinkage at the W/B ratio of 0.45, although this negative effect is mitigated as the W/B ratio decreases. Mercury intrusion porosimetry and scanning electron microscopy analyses reveal that RCFA improves concrete performance by reducing microporosity and enhancing the interfacial bonding between fine aggregates and hydration products.