Structural impact resilience of lightweight fiber-reinforced LECA concrete using ANN and RSM technique

The structural impact resilience of lightweight Lightweight Expanded Clay Aggregate (LECA) concrete refers to its capacity to withstand impact and other related loading effectively. Achieving a balance between lightweight properties and structural performance is crucial; however, research in this scope remains limited. This study explores these characteristics by evaluating the concrete’s ability to absorb impact energy, crack resistance relative to compressive strength, and its residual life. The concrete mix incorporates polypropylene fibres (PPF) between 0 % and 3 %, and the natural aggregate is entirely replaced with LECA. Slab specimens of varying thicknesses were subjected to varying low-velocity impact loadings and the results at both service and ultimate state were analysed using ANN and RSM. Intricate relationships between the material’s composition and its overall impact behaviour demonstrated a strong correlation with PPF below 1.0 % showing notable effects on workability, compressive, split tensile and flexural strengths while contributing to a density reduction. A general improvement in impact resilience parameters is observed in direct proportion to PPF and thickness – up to 33 times in impact energy absorption and up to 17 times in crack resistance. However, higher residual strength is exhibited in concrete with lower thickness due to its greater toughness, further highlighting a significant influence of the fibre-to-concrete dimension ratio on the impact resilience of the concrete. Moreso, results from both ANN and RSM demonstrated strong agreement in all responses within a 95 % confidence interval and R-square of 0.987. • The structural impact resilience of lightweight LECA concrete is investigated. • Energy absorption and crack resistance relative to compressive strength are explored. • Impact resilience parameters are predicted using ANN. • Residual strength of LECA concrete explored relative to fibre content and thickness.