Steel fiber distribution and orientation in full-scale walls cast from FRC with various consistencies and casting procedures: evaluation by the inductive method

Abstract

Steel fiber reinforced self compacting concrete has high potential application in structural elements. The distribution and orientation of fibers in fiber reinforced self compacting concrete play a key role in defining the mechanical and durability behavior. Several factors such as casting method and rheological properties of concrete may influence the fiber distribution and orientation within structural elements. In this paper, due to the importance of vertical elements and high uncertainties regarding fiber distribution and orientation in these elements, steel fiber dispersion and alignment were investigated. In this study, five structural walls (7.0 × 2.5 × 0.2 m) with three distinctive casting procedures (single point, double points, and continuous casting) and two rheological properties [self compacting concrete (SCC) and vibrated compacted concrete] were constructed. Thereafter, by using the inductive test, fiber orientation and distribution were assessed. The results indicated that using two casting points resulted in a more uniform fiber distribution. A comparison between the two SCC mix designs revealed that large coarse aggregates significantly increased segregation and scattering in fiber distribution and orientation. Additionally, fiber orientation analysis demonstrated that continuous casting and vibration led to greater fiber alignment in the horizontal direction. Finally, the results showed that the rheological behavior of concrete mix plays a major role in the fiber distribution compared to the casting procedure. Therefore, to achieve higher uniformity, altering mix designs is recommended.