ABSTRACT
Abstract This paper deals with the tension softening diagram and the size effect on flexural strength of steel fiber reinforced concrete (SFRC, 1% vol. of fiber) beams. Loaddisplacement curves of SFRC beams in various sizes were examined both experi mentally and analytically. Tension softening diagram was determined through modified J-integral based method. Load-displacement curves of SFRC beams (depth: 10, 20, 40 cm) are simulated and the results are in good accordance with the test results. There are two peak loads in the load-displacement curve of SFRC beams and the second peak load becomes greater than the first one when the size of specimens becomes greater. Numerical analysis can fairly explain that the first peak load of SFRC beams depends on the matrix resistance and that the second peak load appears to depend on the resistance due to the fiber reinforcement. Size effect was recognized for flexural strength of SFRC beams. Bending strength corresponding to the first peak load decreased with the increase of size and the gradient was similar to that for normal concrete. The strength to the second peak load also decreased with the increase of size, though the slope became gentle. Keywords: Steel fiber reinforced concrete, Fracture mechanics, Tension softening, Flexural strength, Size effect, Load-displacement curve.
