Flexural fatigue strength and failure probability of concrete beam containing nano-silica and steel fibers

Roller-compacted concrete (RCC) shares components with conventional concrete but differs in aggregate size, workability, mix design, and construction methods. In pavements, repeated loading induces cracks that propagate over time, leading to fatigue failure. This study investigates improving the mechanical properties, flexural fatigue performance, and durability of RCC by incorporating nano-silica and steel fibers. Fatigue tests were conducted to evaluate 28-day flexural performance, and the number of cycles to failure at different stress levels was recorded. Fatigue-life data were analyzed using graphical methods, the method of moments, and maximum likelihood estimation to determine Weibull distribution parameters and hazard functions. Results demonstrate that adding nano-silica and steel fibers significantly enhances fatigue resistance, mechanical strength, and durability. Consequently, pavement thickness can be reduced, lowering both material usage and construction costs, while improving long-term performance. These findings highlight the effectiveness of nano-silica and steel fibers in producing more durable and cost-efficient RCC pavements.