Effect of fibers on stress–strain behavior of concrete exposed to elevated temperature

Abstract

Addition of fiber enhances the engineering properties of concrete. Effect of elevated temperatures on the compressive strength and stress–strain relationship of concrete are presented in this paper. The behavioral efficiency of fiber reinforced concrete (FRC) is far superior to that of plain concrete and many other construction materials of equal cost. Aim of this study is to evaluate the mechanical properties of various fiber reinforced concrete systems, containing individual steel fibers (SF), polypropylene (PP) fibers and hybrid combination of steel and PP fibers with and without exposed to elevated temperature. The total dosage of fibers in concrete was maintained as 0.5%, 1%, 1.5% & 2%. Specimen with 2% SF achieved a maximum compressive strength of 40 MPa before heating, and fiber content with 1.5% of concrete exposed to 1 h duration (925 °C) possess a maximum strength of 28.92 MPa. Addition of PP fibers with 0.5–2% shows marginal variation in compressive strength, maximum strength of 28 MPa is achieved for 1.5% fiber content before heating. Specimen subjected to elevated temperature with 1.5% PP shows a maximum strength of 20 MPa. Hybrid fiber (SF + PP) exhibited a maximum strength of 36 MPa for 2% fiber content before heating, whereas after heating the concrete attains a strength of 24.96 MPa. Contribution of PP fiber in preventing micro-cracks was more pronounced for concrete exposed to 1 h duration.