Pullout behavior of single arc-shaped steel fiber from brittle SIFCON matrix with various embedment lengths and inclination angles

This study aimed to experimentally investigate the pullout behavior of single arc-shaped steel fiber embedded in a slurry-infiltrated fiber concrete (SIFCON) matrix. Three types of steel fibers, namely, hooked-end (2BS), arcshaped I (1BA), and arc-shaped II (2BA), were examined, each with three different embedment lengths (8 mm, 12 mm, and 16 mm) and four distinct inclination angles (0 degrees, 15 degrees, 30 degrees, and 45 degrees). The test results revealed that the pullout behavior between arc-shaped and hooked-end steel fibers was essentially different. Remarkably, 2BA fiber exhibited superior bond performance compared to 2BS and 1BA fibers, attributed to the common contribution of body arched portion and double bend at both ends. In the case of the same inclination angle, increased embedment length led to higher peak loads, more excellent fiber strength utilization ratios, and increased pullout energy, regardless of the steel fiber shapes. However, the average bond strength significantly decreased as the embedment length increased. Furthermore, the peak load, fiber strength utilization ratio, and average bond strength initially increased and then decreased with the inclination angle, regardless of the steel fiber shape. It is found that better bond performance was observed at inclination angles of approximately 15 degrees or 30 degrees.