Enhancing matrix-fiber bond and mechanical performance with high-performance plasticizers

This study explores the influence of sodium gluconate (SG), an organic electrolyte, on the rheology and mechanical properties of ultra-high-performance fiber-reinforced concrete (UHPFRC).SG was incorporated at varying dosages (0.03%-0.15%) to assess its effects on workability, hydration, porosity, and fracture behavior.Key findings demonstrate that SG effectively retards hydration by inhibiting gypsum dissolution and AFt formation, resulting in significant delays in setting time-up to 295% with higher SG content.Furthermore, increased SG dosages improved workability, with a slump diameter increase of up to 56%, facilitating better fiber distribution and bonding.No major chemical changes were observed in the concrete matrix; however, SG decreased macropores (> 10m) and increased micropores (< 0.1m), which contributed to enhanced mechanical performance.Compressive strength rose by 9.5%, and flexural cracking initiation improved by 38% for Mix-0.15.Residual flexural strengths also showed substantial increases (up to 38%), attributed to improved fiber-matrix adhesion.These findings highlight SG's potential to improve UHPFRC's mechanical properties and durability, making it a promising additive for high-strength construction applications.