Approaches for the design of structures made by concrete reinforced with sustainable fibres

In this section design recommendations for Fibre Reinforced Concrete and Cementitious Composites (FRCC) are presented, with main reference to the ones proposed by RILEM TC 162-TDF for SFRC and the ones proposed by CEB-FIP Model Code 2010 (MC2010). As a matter of fact, no specific reliable design recommendations are available so far for concrete reinforced with sustainable, either recycled or natural, fibres due to the relative novelty of these composite materials. However, when short discrete natural or recycled fibres, herein encompassed within the common wording of sustainable fibres, are used as a randomly distributed reinforcement in a concrete matrix, the design recommendations of the MC2010 can, in general, be adopted for the design of sustainable FRCC elements. Nevertheless, to the aforementioned purpose, the fibre reinforced composite materials have to be experimentally characterized according to the procedures described in Section 2.2.2.5, in order to obtain the residual flexural tensile strength parameters (fRj) to model the post-cracking behaviour. Some design tools are also proposed to design specific aspects of sustainable FRCC, such is the case of composites reinforced with continuous (long) vegetable fibres.