Multi-scale analysis on the tensile properties of UHPC considering fiber orientation

Abstract The effect of fiber orientation distribution on the multi-scale tensile properties of ultra-high performance concrete (UHPC) was investigated. Firstly, the orientation tensor description used to characterize and calculate the orientation properties of non-aligned short fiber composites were analyzed. The tensile tests of UHPC with four different fiber contents were carried out. On the basis of analyzing the characteristics of the tensile fracture, the fiber orientation characteristics near and far from the fracture surface were investigated by the image processing. Then, the orientation distribution function (ODF) of non-aligned inclusions was reconstructed by using the hybrid closure approximation method. The feasibility of the method for UHPC was verified by comparing the reconstructed ODF with the experimental ODF. Finally, the elastic properties of UHPC considering the fiber orientation were calculated by the two-step mean field homogenization method. On this basis, combined with Puck failure criterion, the tensile strength of UHPC with different fiber content and orientation tensor was predicted.