Results and Discussion

Fibre Orientation and Distribution

Table 2 includes the fibre distribution parameters obtained by image analysis. N and Nefff were higher in the specimens with the notched plane parallel to the expected concrete flow direction. These values decreased as the notched plane rotated towards to the perpendicular position regarding the flow direction (Fig. 1b). For the case of the notched plane orientation в = [0-15°[, N^ was approximately 76, 156 and 686 % higher than when P was between [15-45°[, [45-75°[ and [75-90°] intervals, respectively. A higher value for the fibre orientation factor, цв, was also obtained for the series with a P = [0-15°[, having been 8, 20 and 30 % higher than the one obtained for the series [15-45°[, [45-75°[ and [75-90°], respectively. This could be ascribed to a preferential fibre alignment, which was influenced by the flowability of concrete that induces the fibres to be reoriented and remain preferentially perpendicular to the concrete flow direction. The fibre segregation parameter, ?seg, was slightly higher than 0.5 indicating the occurrence of a slight segregation of the fibres, caused by the highest specific weight of the steel fibres amongst the constituents of the SFRSCC.

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