Application of high-strength steel fiber-reinforced concrete to reduce the use of conventional rebars in normal-strength reinforced concrete beams

This is an experimental study whose main objective was to evaluate the use of high-strength steel fiber-reinforced concrete (HSSFRC) to reduce the use of conventional reinforcements, longitudinal/transverse steel bars in normal-strength reinforced concrete beams (NSRC). To enable a detailed discussion on the theme, five prototype beams (150x300x2700 mm3) were built and load tested until failure. One of the beams contained no fibers and was used as control. It had a strength class of 30.0 MPa, and longitudinal reinforcement ratio, ρl,t, and transverse reinforcement ratio, ρw, of 0.91 and 0.11%, respectively, which are the values commonly used in practical applications. In addition to the control beam, four other HSSFRC beams, with a strength class of 60.0 MPa, were built with ρl,t = 0.39% (reduction of ≈ 60.0%, in comparison to the control beam), and ρw = 0.0% (reduction of 100.0%); fiber consumption ranged between 45.0, 60.0, 75.0 and 90.0 kg/m3. The behavior of the beams was interpreted on the basis of the load-displacement and moment-curvature relationships. These results, and the responses of the material characterization tests, showed the feasibility of designing HSSFRC beams with undoubtedly successful reductions, and mechanical behavior which was equivalent, in some cases, to that of NSRC beams.