Experimental Evaluation Of Flexural Response In Steel Fiber Enhanced High Performance Concrete Beams

Abstract

This research presents an experimental investigation into the flexural behavior of High Performance Concrete (HPC) beams incorporating varying volumes of hooked-end steel fibers. While HPC exhibits excellent compressive strength and durability, its brittleness under flexural loading is a key limitation. To address this, steel fibers were introduced at volume fractions of 0%, 0.5%, 1.0%, and 1.5%, and twelve beam specimens were tested under four-point bending following ASTM C1609/C1609M standards. The study evaluated critical parameters including first crack load, ultimate load, load-deflection characteristics, crack propagation, and failure mode.Results indicate that the inclusion of steel fibers significantly enhances flexural strength, ductility, and energy absorption capacity. Beams with 1.5% fiber content showed a 45% increase in peak load and a threefold increase in ultimate deflection compared to control specimens. Crack control also improved, with multiple fine cracks forming instead of a single wide crack. The mode of failure changed from brittle to ductile with increasing fiber dosage. These findings demonstrate the effectiveness of steel fibers in transforming HPC into a more resilient and flexure-tolerant material, making it suitable for critical structural applications such as earthquake-resistant buildings, bridge decks, and precast elements.