Interfacial response of fibre-to-matrix in textile reinforced concrete between two cracks: Analytical solution

Textile reinforced concrete (TRC) has been increasingly used in strengthening existing structures and building new lightweight structures, and the interfacial bond plays a fundamental role in optimising the structural performance and design. This paper, for the first time, presents an analytical solution to predict the interfacial response of a textile reinforced concrete composite between two cracks. The closed form expressions not only apply to predict pull-out force vs. displacement relation, but also simulate interfacial response between two locations. The interfacial behaviour, including the interfacial relative slip, the shear stress distribution, and the axial stresses of the reinforcement and the matrix, could be obtained. While the numerical parametric studies are based on carbon fibre textile reinforced concrete, the theoretical solutions are applicable to other embedded type reinforced composites. The accuracy of the derived theoretical model has been validated using previously published researches of similar problems and the FEM simulation. The numerical parametric studies concluded that increasing the load difference at the two ends of the reinforcement (increasing β value) may shift the critical failure mode from interfacial debonding to material yielding. Furthermore, using micro/short fibres in the concrete matrix (triggering a negative η value) will significantly improve the interfacial performance. It is also found that for a concrete composite with a high reinforcement ratio, it is necessary to use either ultra-high strength concrete or fibre reinforced concrete matrix to fully use the high tensile strength capacity of carbon fibres.