Mechanical characterization of SFRC with annealed and galvanized steel fibers by different test typologies

Abstract

Steel fiber reinforced concrete (SFRC) is a composite material with randomly distributed fibers, which improve the concrete's post‐cracking residual strength and toughness. Usually, the micromechanical performance of single fibers is studied under pullout tests, analyzing its load–slip relationships, which translate the bond behavior between the fiber–concrete interface. In this research, three different test typologies, summing up 110 trials, were performed to analyze the influence of distinct parameters on the fiber pullout behavior, such as tensile strength, friction, shape, embedded length, and position. The fibers were manufactured using local steel (annealed and galvanized wires). The results showed that the materials used have a significantly lower tensile strength than the ones used in industrial fibers, that is, 7 times lower. However, the interaction fiber–concrete tested under pullout strength was similar between annealed, galvanized, and industrial steels. Also, the data were analyzed using statistical tests as a criterion to find the parameters with a significant difference in the responses. The statistical analysis pointed out that the main parameters that control the mechanical behavior of the fiber–concrete interaction are the fiber shape and embedded length. The pullout efficiency showed that the highest performance was on specimens with low embedded length.