Mechanical Performance of OPC-53 Based Engineered Cementitious Composite (ECC): Split Tensile Strength and Flexural Strength Evaluation with Varied Fiber Reinforcement

Abstract

This paper presents a focused experimental investigation into the mechanical performance of Ordinary Portland Cement (OPC Grade 53) based Engineered Cementitious Composite (ECC) matrices reinforced with three fiber configurations: hooked-end steel fibers, Recron 3S polyester micro-fibers, and a hybrid combination of both. Coarse aggregates were entirely eliminated to conform to ECC micromechanical design principles, ensuring uniform fiber dispersion and strain-hardening capacity. Cylindrical and beam specimens were cast and cured for 7 and 28 days before being subjected to split tensile strength [IS 516 (Part-2):1999] and flexural strength [IS 516 (Part-1):2021] tests. Among all OPC mixes, the 0.8% steel fiber formulation achieved the highest split tensile strength of 5.75 MPa at 28 days — a 91% improvement over normal concrete — while the 2.4% steel fiber mix delivered the peak flexural strength of 18.50 MPa at 28 days. Excessive fiber dosages (2.4%) for Recron 3S induced fiber balling and workability loss, reducing 28-day strength values. The hybrid (1% Steel + 1% Recron 3S) configuration provided a balanced multi-scale crack-bridging mechanism, achieving 4.33 MPa split tensile and 9.66 MPa flexural strength at 28 days, though synergistic performance was constrained by workability limitations.