Multidirectional double punch test to assess the post-cracking behaviour of FRC

Several authors have shown the direct influence of the orientation of the fibres on the residual strength of the material. From a design-oriented perspective, the anisotropy due to the dispersion and orientation of fibres has to be taken into account when characterizing the mechanical behaviour of the material. However, the wide variety of tests currently used for the characterization of fibre reinforced concrete (FRC) only allow a unidirectional characterization (without considering the orientation of the fibres in the matrix). In order to overcome this drawback, a complete characterization of the fibres orientation together with its structural contribution in the cracked section is required. Considering the above, this paper proposes the use of the double punch test on cubic samples (so called multidirectional double punching test or MDPT test) as an alternative to conventional characterization tests. Due to the specimen shape in a single procedure an estimation of the fibre orientation efficiency can be obtained, establishing a link between the mechanical properties of FRC with the fibre orientation. Thereby, this paper represents a meaningful contribution to provide a step towards the development of a rational and design-oriented constitutive model for real-scale structures.