X-ray computed tomography harnessed to determine 3D spacing of steel fibres in self compacting concrete (SCC) slabs

• Engineered steel fibre are important type of concrete reinforcement.
• SCC and FRC are combined into one type of cement composite.
• We examine fibre spacing in FRC–SCC slabs.
• X-ray computed tomography is harnessed to conduct the tests.
• Distribution and spacing analysis of fibre has been performed.

The conducted research programme was focused on fibre spacing in SFR-SCC slabs. SCC slabs with two steel fibres types and different casting points were examined. A distribution and spacing analysis of fibres has been performed. Their number and volume were evaluated along the slab main axis. The distribution of fibres in slabs cast using different techniques have been compared. The amount of fibres in the upper and lower slab halves has been analysed. The uniformity of spacing of fibres was assessed. The angles between the fibres and the beam main axis were examined. Graphical visualization using 4D spherical histograms for quick assessment of fibres orientation is also presented.