Numerical modeling of steel fiber reinforced concrete spallation exposed to medium loading rate

Abstract

Properties of unreinforced concrete and cement-based matrix are well understood. One of the issues with the cement-based matrix is its inherently brittle failure when exposed to loading. As such, steel fibers were proposed to enhance the ductility of cement-based and concrete materials. Ever since, Fiber-Reinforced Concrete (FRC) has become a commonly used building material in many construction activities such as bridges, airport pavements, shotcrete, and many others. According to previous research, the addition of steel fibers, typically from 20 to 50 kg/m3 into the conventional concrete, can significantly enhance many of the desired engineering properties of hardened concrete such as flexural strength, tensile strength, micro-cracks as well as splitting. This research presents a study aimed to numerically investigate the influence of steel fibers on the dynamic behavior of Plain Concrete (PC) exposed the tensile loading at medium strain-rate. The influence of steel fibers is investigated using different fiber volume fractions ranging from 0.0 to 4.5%. The Modified Split-Hopkinson-Bar (MSHB) apparatus is employed to investigate the dynamic tensile behavior of PC and Steel Fiber-Reinforced Concrete (SFRC). Validation of the finite element model and constitutive material behavior is carried out with the comparison of computed and measured experimental pull-back velocities of the specimen’s free end. The results showed that impact properties of steel fibers exhibit significant improvement in the toughness and the dynamic tensile strength of concrete and higher fiber volume fraction is more effective in enhancing the mechanical properties of SFRC composite.