Enhancing flexural performance of layered SCC beams with polypropylene fibre reinforcement

This study explores a layered approach to fibre reinforcement for enhancing the flexural behaviour of self-compacting concrete beams. Polypropylene fibres were placed in tension zones of the cross-section to improve efficiency and utilization. The optimal mix with 0.075% fibre achieved 13.88% higher compressive strength and 15.47% higher tensile strength than the control concrete mix. Durability also improved, with water absorption reduced by 37.03% and chloride ion penetration reduced by 25.64%. Flexural testing was carried out on five beam configurations with fibres at full depth, bottom half, and one-third depth above and below the reinforcement. Half-layered beams with fibres above the tensile reinforcement reached an ultimate load of 149.20 kN and a ductility index of 6.68. They nearly matched fully reinforced beams while using only half the fibre content, offering structural and economic benefits; fibre placement below the reinforcement gives negligible gains. The findings confirm that targeted fibre placement enhances crack resistance, ductility, and energy absorption while reducing fibre use.