Structural Response of Concrete Slabs Hollowed with PVC Pipe Formers

Abstract

This empirical study investigates the structural behavior of hollow concrete slabs utilizing
PVC pipes as void formers, focusing on load bearing capacity, deflection characteristics, and
material optimization. The research employed experimental analysis of 24 reinforced
concrete slab specimens with varying void ratios (0%, 15%, 25%, and 35%) and PVC pipe
diameters (75mm, 100mm, and 125mm). Testing procedures included flexural strength
analysis, deflection measurement, and failure mode assessment under stati c loading
conditions. Results demonstrate that hollow concrete slabs with 25% void ratio achieve
optimal structural performance, exhibiting 12% reduction in self weight while maintaining
85% of solid slab flexural strength. The study reveals that PVC pipe diameter significantly
influences crack propagation patterns and ultimate load capacity. Deflection analysis
indicates that slabs with 15% void ratio show minimal deviation from solid slab behavior,
while 35% void ratio specimens exhibit 28% increased defl ection at service loads. Cost
benefit analysis demonstrates 18% material savings with hollow slab construction. The
research concludes that PVC pipe void formers provide an effective solution for sustainable
concrete construction, offering substantial weig ht reduction and material economy without
compromising structural integrity when properly designed and implemented within
recommended void ratio limits.