Probability distribution functions to characterize the orientation profile of SFRC

Abstract

Steel Fiber Reinforced Concrete (SFRC) still deserves much research because some aspects of its tension response have to be better predicted. It is accepted that the mechanical properties are intimately linked to the fiber orientation within the matrix. To determine the contribution of the fibers to the tension response is necessary to know as precisely as possible the amount of existing fibers and their orientation. Computerized Tomography (CT) is the most effective way to determine the orientation of the fibers embedded in the concrete. An experimental program consisting of analyzing 34 cylindrical cores, extracted from 9 SFRC beam specimens made with three different fiber amounts, was performed. An image recognition software was developed for determining the position and orientation of the fibers from the scans. Fiber orientation has been quantified by the two most common parameters, the orientation number and the director. The influence of factors such as the fiber content, the direction of flow or the separation to the mold walls in the fiber orientation is analyzed. Finally, a research for the best fitting probability distribution function is presented and discussed.