Investigation into Enhancing Methods for Apparent Performance and Durability of Fair-Faced Self-Compacting Concrete

Self-compacting concrete (SCC) offers the advantage of being vibration-free, effectively addressing the challenges associated with vibration in densely reinforced areas. However, modern building structures increasingly demand enhanced apparent quality from concrete. Currently, there is a lack of relevant research on the apparent performance and durability of fair-faced self-compacting concrete (FFSCC). Firstly, the effects of formwork, release agent, and defoamer on the apparent performance of FFSCC were investigated. The results indicated that the apparent quality of FFSCC specimens cast using glass fiber–reinforced plastic (GFRP) formwork is superior, exhibiting a reduction in bubble content on the surface by 33%, 55%, and 89% compared with specimens cast with steel, wood, and PVC formwork, respectively. The use of a concrete release agent significantly enhanced the apparent performance of FFSCC, with water-based release agents outperforming their oil-based counterparts and preventing color differences. The inclusion of a defoamer markedly improved the apparent performance of FFSCC when PVC formwork was employed. Secondly, the effects of the W/B ratio and fair-faced concrete protective agent (FFCPA) on the anticarbonation performance of FFSCC were investigated. The permeable fair-faced concrete protective agent (PFFCPA) demonstrated greater efficacy in enhancing the carbonation resistance of FFSCC compared with the film-forming fair-faced concrete protective agent (FFFCPA). A prediction model for the carbonation depth of FFSCC, which considers the W/B ratio, carbonation time, type, and thickness of the protective agent, was proposed. Finally, microscopic tests were conducted to elucidate the film-forming and penetration protection mechanisms of FFCPA. The optimum pouring details for FFSCC were recommended: the use of GFRP formwork, a water-based release agent, an appropriate amount of defoamer, and PFFCPA when durability protection is considered. This study contributes to the popularization and application of FFSCC in engineering.