Optimizing of Steel Fiber Reinforced Concrete Mix Design

Cementitious matrices are the fragile materials that possess a low tensile strength. The addition of fibers randomly distributed in these matrices improves their resistance to cracking, substantially. However, the incorporation of fibers into a plain concrete disrupts the granular skeleton and quickly causes problems of mixing as a result of the loss of mixture workability that will be translated into a difficult concrete casting in site. This study was concerned on the one hand with optimizing the fibers reinforced concrete mixes in the fresh state, and on the other hand with assessing the mechanical behavior of this mixture in the hardened state, in order to establish a compromise between the two states. In the first part of this paper, an experimental study of an optimization method of fibers reinforced concrete while taking into account of some parameters related to the matrix e.g. volume of the admixture, volume of incorporated fibers and the volume of water and, cement (W, C) in function of workability time are presented. Finally, test specimens of mixture optimized by this method have been tested in compression and tension due to bending. The results have been compared with those of mixture test specimens optimized by Baron – Lesage method.