Flexural Toughening of a Cementitious Mortar Reinforced with Wave-Shaped Short Plastic Fibers

This article assesses the effects of corrugated-shaped polymeric fibers at varying aspect ratios and fiber contents on the flexural behavior of fiber-reinforced mortars (FRMs). Three weight fractions (0.5%, 0.7% and 1.0%) and two aspect ratios of 37 and 46 were respectively investigated. The results highlighted that the flexural features vary significantly because of corrugated plastic fiber addition. Compared to unfilled mortar, the maximum flexural strength of the composite samples increases up to 31.4% and 67.8% for the I20 and I25 fibers, respectively, at 0.5 wt.% fiber loading. At low fiber content, the reinforcing action on the flexural strength is very limited for I20 fibers with an incidence of 6.9% for the composite with 0.5 wt.% fibers (aspect ratio 37). Furthermore, the toughness index (TI) values, identified as the toughness energy at a specific deflection, are in the range of 20–50 for a bending deflection equal to 1/20 of the span length. The maximum TI was reached for composite mortar batch characterized by 1 wt.% 25-mm-long fibers. Moreover, despite the plain concrete, FRM composites exhibited a ductile-like behavior with large residual strength after fist crack activation also at low plastic fiber content.