Influence of the cementitious matrix on the behavior of fiber reinforced concrete


One of the main purposes of the addition of fibers to the concrete is the control of the plastic shrinkage cracking in the fresh state and the increase of the post-cracking resistance in the hardened state. The cementitious matrix is one of the factors that influences the performance of fiber reinforced concrete, interfering in the fluidity of the mixture and in the adherence between fiber and matrix. In this context, the present paper evaluates the behavior of two concrete, one of conventional strength and another of high-strength, without fiber and with a content of 1%, by volume, of fiber, being used steel fibers and polymeric macrofibers. For this, the mechanical properties of the concrete were evaluated in the hardened state by the tests of compressive strength, Barcelona, flexure of prisms and punching of plates. From the experimental results, statistically analyzed, there were significant changes in toughness and residual strength due to change in the cementitious matrix. Finally, an equivalence of performance between the fibers as to the toughness was observed, with the change of the cementitious matrix.