Beams of fibrous concrete in shear and bending: Experiment and model

Beams of high-strength concrete (f(cc) up to 90 MPa) were tested in shear and bending. Various types of fiber (metallic and nonmetallic) were added to the concrete matrix to up to 1% per volume concrete. Also, four different beam depths were investigated. The efficiency of fibers depends on the governing load-carrying mechanisms, which may vary for different beam dimensions. The chosen steel fibers did not improve the capacity of the 250 mm deep beams as they did for some of the 300 mm beams. They enhanced the toughness in the 500 mm beams, but were not enough for the 700 mm beams. Also, a fiber cocktail may prove more effective than using a single type of fiber. The chosen steel fibers are competitive with conventional stirrups, according to this study. A nonlinear truss model is devised to predict the load-carrying capacity of the beams. The model gave good predictions for beams without stirrups and depths up to 500 mm.