The influence of the fibers on the structural responses of reinforced concrete beams

High-performance and fiber-reinforced concretes are receiving growing attention because of their physical and mechanical properties. The appropriate mix of cementitious matrix, additives and fibers create a very large class of materials, requiring a careful design for each particular application. Typical applications of these materials include concretes for very severe environmental conditions, replacement or integration of traditional steel reinforcement, improvement of structural ductility. The large variety of these materials and the substantial absence of design guidelines for structural members is evidenced by a large number of experimental studies on high-performance and fiber-reinforced concretes, whose interpretation by a theoretical model is often nontrivial. The mix and reinforcement design of structural members for this class of materials is one of the more important difficulties to overcome for their diffusion in engineering applications. Moreover, the realization of full-scale models is often not feasible due to the very large loads required for testing. Consequently, size-effect influence has to be accounted for in the interpretation of the experimental results.