Stress-Strain Curves for High-Performance Fiber Reinforced Concrete under Compression

Abstract

Steel fiber reinforced concrete (SFRC) is increasingly being used day by day as a structural material for various applications. The complete stress-strain curve of this material in compression is needed for the analysis and design of structural elements. An experimental investigation was carried out to generate the complete stress-strain curve of high-performance fiber reinforced concrete (HPFRC) with a strength range of 52–80 MPa. The variation in concrete strength was achieved by varying the water-to- cementitious materials ratio from 0.40 to 0.25, at 10% silica fume replacement. Crimped steel fibers with fiber volume fractions of 0.5%, 1.0% and 1.5%, and aspect ratio of 80 are considered in this study. The effects of these parameters on the shape of stress-strain curves are presented and discussed. Test results indicate that inclusion of steel fibers improves the compressive and flexural strengths, enhances the strain at peak stress, and ductility and toughness of concrete. Equations are proposed to quantify the effect of fibers on compressive strength, strain at peak stress and toughness of concrete in terms of fiber reinforcing index, and elastic modulus as a function of compressive strength. The proposed equations have been found to give good correlation with the experimental values. Keywords: crimped fibers; fiber reinforcing index; high-performance fiber reinforced concrete; compression; stress-strain curve; toughness. Journal of Civil Engineering Research and Practice Vol. 5 (1) 2008: pp. 1-14