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

• The MDPT is a double punch test applied on cubic specimens for the post-cracking characterization of FRC.
• The test can be used to assess the toughness and residual tensile strength of FRC considering the orientation of fibres.
• A simple approach for determining the orientation of the fibres by means of mechanical results is presented.

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). However, 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. In this paper, an alternative to the conventional tests applied for the characterization of FRC is proposed. The multidirectional double punch test (MDPT) consists of a double punch test applied to a cubic specimen. 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.