Velocity gradients of concrete mass reconstructed based on measured fibre orientations in hardened concrete

Abstract

During the casting of steel fibre reinforced concrete (SFRC) the orientation of fibres is influenced by flow dynamics of concrete mass. A simple theoretical model presented allows the calculation of velocity gradient matrices for concrete mass based on steel fibre orientations measured in the hardened concrete samples taken from the different regions in the slabs. This made it possible to examine the realistic trends of the flow near the formwork or free surface or in the bulk material. Eigenvalues and eigenvectors of the matrices show the directions of the maximal and minimal velocity changes, which can be compared in different positions of the slabs. The outcomes of the study can contribute to controlled production technology of SFRC.