Influence of the rheological properties on the steel fibre distribution and orientation in self-compacting concrete

Elena Jasiuniene, Vaidotas Cicenas, Paulius Grigaliunas, Zymantas Rudzionis, Arunas Aleksandras Navickas - Prof. K. Barsauskas Ultrasound Research Institute, Kaunas University of Technology, Kaunas, Lithuania; Department of Electronics Engineering, Kaunas University of Technology, Kaunas, Lithuania; Department of Building Materials, Kaunas University of Technology, Kaunas, Lithuania.

The interest in potential applications produced with self-compacting fibre reinforced concrete continues to grow, but in practice, problems associated with an uneven distribution and orientation of fibres in the concrete structure occur. It is not clear what exactly influences uneven distribution of fibres in selfcompacting concrete (SCC) mixtures, especially during the casting and how different factors influence fibre orientation. The objective of this work was to investigate how rheological properties influence the steel fibre distribution in self-compacting concrete. This work also focuses on the investigation of steel fibre spatial orientation dependence on rheological properties of SCC, while keeping other casting parameters and the proportions of mixture components constant.(…) The steel fibre orientation, volumetric concentration and spatial distribution values were determined in separate beam sections using three different non-destructive testing methods: electromagnetic induction, image analysis and computed tomography (CT scan).

How Amira-Avizo Software is used

For the fibre extraction from the tomographic data the Avizo software was used. The fibre detection and calculation algorithm was divided to a few parts. Firstly, correlation fields using Fourier transformation were calculated. Secondly, the correlation between the image and the cylinder template was computed, as the fibres used for the production samples have a cylindrical form. Cylinder template parameters were chosen according to physical fibre parameters used in the reinforced concrete samples. Two correlation fields were calculated: one of them stored the maximum correlation value for each voxel and the second contained the orientation direction that corresponds with the maximum value. Third, a line tracing was performed. The condition parameters of minimum line seed correlation value for the beginning of the line and the minimum correlation value for the continuation of the line must be fulfilled. At the end of the tracing all the correlation values exceeding the seed correlation value were used to construct the fibres. The detailed algorithm of tracing the lines is presented by Weber and it was implemented in Avizo XFiber  software module.