Stress-strain relationship of high-strength fiber concrete in compression

Tests conducted to characterize the stress-strain relationship of high-strength fiber concrete in compression using both cylindrical and prismatic specimens are reported. The concrete strength investigated ranges from 70 to 120 MPa. Other parameters include volume fraction of steel fibers and direction of casting in relation to the loading axis. Test results indicate that inclusion of fibers improves the strength and enhances the strain at peak stress but results in a smaller initial tangent modulus for specimens cast in an upright (vertical) position. Vertically cast prisms provide higher strains at peak stress and better postpeak ductility than cylindrical specimens. Based on the test data, an analytical model is proposed to generate the complete stress-strain sigma-epsilon curves of high-strength fiber concrete derived from cylinders and horizontally cast prisms. The proposed model has been found to agree well with the stress-strain curves generated experimentally.