The Effect of Fiber Volume Fraction on Fiber Distribution in Steel Fiber Reinforced Self-Compacting Concrete

This paper investigates the effect of fiber volume fraction on fiber distribution in steel fiber reinforced self-compacting concrete (SFRSCC) through experiments and numerical simulations. Three types of SFRSCC beam specimens with different fiber volume fractions (0.3%, 0.6%, and 0.9%) were cut to expose the steel fibers. The number and the orientation angle of the steel fibers on the beam sections were determined by image analysis techniques. Fiber density, fiber segregation coefficient, fiber dispersion coefficient and fiber orientation coefficient were applied to evaluate fiber distribution on the beam sections. Based on the experimental data, numerical models simulating the pouring process of fresh SFRSCC were established to analyze the overall fiber distribution in the specimens. The results show that the distribution state of the fibers on the beam sections is not random and uniform, which is correlated to the fiber volume fraction. Due to the variable rheological properties, a greater fiber volume fraction causes better fiber uniformity, lower fiber segregation and worse fiber alignment on the beam sections. Meanwhile, the numerical results show that the distribution law of fibers along the length direction of the specimens is almost independent of the fiber volume fraction. In addition, increasing the fiber volume fraction results in the increase of the average angle of the fiber orientation in the specimens. The results can provide a reference for optimizing the fiber distribution in the concrete matrix.

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