A unified formulation for simulating the bond behaviour of fibres in cementitious materials

This paper presents a unified formulation for simulating the overall bond behaviour of fibres embedded in cementitious matrices. In principle, such a formulation is based on assuming a model between interface bond stresses and the corresponding relative displacements. Two alternative models are actually considered in this paper. The first one is based on a refined fracture-based plasticity model which requires a numerical solution approach; the second one assumes a simplified bilinear relationship and can be handled analytically. Both models, considered in the present formulation, address the behaviour of fibres under tensile axial stresses which result in a “mode II” debonding phenomenon. Finally, numerical results are reported for both validating the proposed models against relevant experimental results and pointing out the differences possibly arising by adopting the two alternative models considered in this paper.

► A unified approach for modelling the fibre-to-concrete bond behaviour is presented.
► Slip initiation in pure shear loading induced by the fibre tensile stress is studied.
► Two alternative constitutive models are proposed.
► A fracture-based model is compared with a classical elasto-plastic softening law.
► Numerical results are discussed and compared against experimental pull-out data.