Investigation on the flexural behavior of high‐strength fiber‐reinforced concrete

The present research investigated the flexural behavior of high‐strength fiber‐reinforced concrete (HSFRC) with six different types of fiber: hooked‐end and crimped steel fibers, chopped and pultruded glass fibers; monofilament and twisted polymeric fibers. An extensive experimental program with 108 specimens for 3‐point bending tests was carried out and the parameters analyzed were the fiber content (0.50%, 0.75% and 1.00% in volume), the fiber type and the compressive strength of the concrete (60 and 90 MPa). Statistical analyses were performed and showed that regardless of the fiber material, increasing the amount of fibers added to concrete increases residual strength and toughness. Limit of proportionality is not affected by the addition of fibers, while postcracking behavior, on the other hand, is controlled by the fibers. Increasing the compressive strength of the concrete matrix affect mainly the limit proportionality of all mixes and the postcracking behavior of the concrete reinforced with hooked‐end steel fibers. The classification of HSFRC and the conditions required for HSFRC for use in structural applications according to the fib Model Code 2010 were also discussed, and it was verified that such conditions are not consistent with the experimental results and should be revised for high‐strength fiber‐reinforced concrete.