FLEXURAL STRENGTH OF FIBER CEMENTITIOUS COMPOSITES

An analytical model has been developed for the flexural strength of fiber-reinforced cement-based materials. The proposed model adopts the fictitious crack concept to relate the flexural strength of these fiber composites to their tension-softening properties and to specimen geometry. For the case of a cementitious matrix reinforced with discontinuous randomly distributed fibers, the flexural strength can be related to the micromechanical parameters and specimen geometry. A reasonable agreement has been observed between the model prediction and experimental data reported in literature, supporting the validity of the proposed model. This model led to conclude that the flexural strength of fiber cementitious composites is dependent on specimen geometry and is also strongly influenced by the stress acting across the process zone. In addition, the flexural strength is always higher than the tensile strength and it is reached when the fracture process zone is only partially developed. The model can be used to design fiber cementitious composites for optimum flexural strength.