Cracking behaviour of concrete beams reinforced with a combination of ordinary reinforcement and steel fibers

The paper presents an experimental and theoretical study on the cracking behaviour of concrete beams having longitudinal tension reinforcement and various combinations of volume and aspect ratio of steel fibers. Five full-scale beams with a concrete compressive strength of 42 MPa were tested. The mechanical properties of the steel fiber concrete under tension were determined by means of the four-point bending test specified in the Belgian standard NBN B15-238. The experimental results show that the addition of steel fibers decreases both the crack spacing and the crack width. A modification of the model of Nemegeeret al. to predict crack widths is suggested.