Rheological and Flexural Properties of High Strength Cementitious Composite Reinforced with L-Shaped End Superelastic Short Fibers

Experimental investigations are presented on the effect of fiber dosage in a high strength cementitious composite (HSCC) with superelastic fibers with an L-shape at both ends. Superelasticity is one of the smart properties of shape memory alloys, and another property is shape memory effect. Out of the superelasticity and shape memory effect, only superelasticity is exploited in this present application. The rheological properties of the fresh composite system are investigated first using the slump flow table test. The slump test shows that although the fibers with L-shaped ends adversely affect the rheological properties of fresh concrete, the consistency of the mix is hardly compromised. The three-point bending test is conducted thereafter to assess the flexural performance of several beam specimens in the hardened state. The results from the three-point bending test are employed to quantify the influence (of fiber dosage) on the post-peak behavior using alternative protocols for the quantifying measures. The increase in fiber content generally increases flexural toughness. However, a fiber content beyond 0.75% in volume is required to achieve post-peak hardening. Alternative standards for evaluating flexural toughness are assessed in reference to the post-peak behavior of the composite system under flexure. The recentering capability using the cyclic three-point bending test is also calculated. Finally, the failure modes of the fiber are assessed to show the combined effect of the anchorage offered by the L-shape of the fibers and the interfacial bond strength. It is observed that the anchorage of HSCC is sufficient to hold the fibers until rupture. The failure modes of the fibers are noted to be irrespective of the fiber content yet sensitive to the orientation and length of embedment.