Flexural performance of hybrid polypropylene–polyolefin FRC composites

Abstract

The objectives of the present study are to conduct experimental studies and determine the flexural strength and ductility of fiber-reinforced concrete (FRC) by adding two types of fibers, namely the polypropylene (PO) and polyolefin (PP) fibers in mono and hybrid forms, and assess the flexural toughness of fiber-reinforced concrete (FRC). The reinforced concrete (RC) beams of size 150 mm × 200 mm × 1000 mm were cast by adding discontinuous fibers of volume fraction (Vf) of 1% of PP (100%), PO (100%) and PP–PO (50–50%) in concrete. The flexural toughness of FRC beams with PP-1%, PO-1% and hybrid-1% (PP–PO) was evaluated from the area under the load–deflection curve and compared with control specimens (CS) (without fibers). The flexural strength and ductility were higher for FRC beam specimens reinforced with hybrid fibers (PP-Vf = 0.5% + PO-Vf = 0.5%) than beam specimens cast with mono PP fibers of Vf = 1% and PO fibers of Vf = 1%, and CS. The flexural toughness (FT) at beam deflection, L/150 (L = span length) and flexural toughness ratio (FTR) were found to be higher for FRC-hybrid PP–PO beam specimens than the specimens reinforced with PP and PO and control specimens (CS). The first-crack width and ultimate crack width of beam specimens were comparatively lesser for hybrid PP–PO than PP, PO fibers and CS.