Study on the factors influencing bending spalling failure in BFRP textile-reinforced concrete

Textile-reinforced concrete (TRC), an innovative combination of fine-grained concrete and textile, facilitates the construction of thin, lightweight structures. Epoxy resin impregnation of textile is commonly applied to improve the mechanical properties of TRC, but it also increases the occurrence of spalling failure, which is not yet fully understood. This study investigates the effects of textile layer number, mesh size, surface treatment, and cover thickness on spalling failure through four-point bending tests conducted on basalt fiber reinforced polymer (BFRP) textilereinforced concrete plates. The results showed that spalling failure compromised load-bearing capacity in post-cracking stage. Increasing the textile layers alleviated spalling damage and significantly improved ultimate bending stress, toughness, and crack development. Enlarging the textile mesh size effectively suppressed spalling failure, while excessively large mesh size inhibited multi-crack development and degrade flexural performance. Sand-coating treatment enhanced interfacial bonding and modified yarn cross-sectional shape, thereby reducing peeling cracks and improving flexural performance, particularly with fine sand. Similarly, fiber-coating treatments yielded improvements, attributed to enhance bonding and bridging effects of short fibers. In contrast, increasing cover thickness exacerbated spalling damage and decreased flexural capacity. Furthermore, spalling failure was preliminarily predicted based on the balance between spalling resistance and peeling force. These findings provide deeper insights into bending spalling failure and contribute to the development of limit state design for TRC structures.