Three-dimensional braided composites as innovative smart structural reinforcements.

[Display omitted] • In this study different polymer-based braided composite rods (BCRs) were successfully developed to reinforce and monitoring of structural elements. • Piezoresistivity and mechanical behaviour of different BCRs reinforced with short carbon fibre, hybrid carbon nanotube/graphene nanoplatelets, and directed carbon fibre were investigated. • The proper piezoresistivity behaviour of the concrete beam reinforced with smart BCRs demonstrated a high potential of this elements in terms of strain and stress detection. This study is a systematic effort focused on the development of feasible self-sensing braided composite rods (BCRs) for structural reinforcement and damage monitoring. In this route, BCRs were produced and reinforced with different carbon-based conductive fillers, including hybrid carbon nanotubes (CNTs)/graphene nanoplatelets (GNPs), chopped carbon fibres (CCFs), and directed (unidirectional) carbon fibres (DCFs) using a specific process. The mechanical and self-sensing performances of the BCRs were evaluated using various tests. Furthermore, a honeycomb 3D system of DCF/BCRs was used to reinforce a 100 mm × 100 mm × 850 mm concrete beam, and the piezoresistivity of the specimen was investigated under cyclic flexural loading with different patterns. The maximum tensile strength and elastic modulus were observed for the BCR reinforced with 1.0% (wt) CCFs. However, the maximum sensitivity was attained for the BCRs with 3.0% hybrid CNTs/GNPs. The analysis of the results and economic assessment showed that DCF-reinforced BCRs are the optimum choice for developing a feasible, reliable, and economic structural health monitoring technique. [ABSTRACT FROM AUTHOR]