Fracture properties of extruded fiber-reinforced mortar with preferentially aligned fibers: Fid-Bau Portal

Fracture properties of extruded fiber-reinforced mortar with preferentially aligned fibers

Alarrak, Rashed / Jeon, Byeonguk / Brand, Alexander S.

Highlights • The fracture properties of fiber-reinforced mortar were enhanced via extrusion. • Extrusion casting had a major impact on increasing the critical crack length. • DIC technique was used to observe CMOD, crack propagation, and localized strains. • The crack deflection mechanism’s effect on fracture was examined via DIC technique. • Mode I and mixed-mode fracture toughness parameters were computed and compered.

Abstract The fracture properties of fiber-reinforced mortar were determined in this paper using three-point bend tests on notched beams and employing the two-parameter fracture model (TPFM). A comparison was made between two casting methods: conventional casting and pump-driven extrusion. The hypothesis suggested that the extrusion process would preferentially align fibers parallel to the tensile stresses, thereby enhancing the concrete’s fracture properties. The results corroborated the enhancement of concrete's ductility and post-peak behavior when fibers were added, consistent with previous studies. However, this study revealed a novel insight that preferential fiber alignment achieved through extrusion could further enhance the fracture properties of concrete. Furthermore, digital image correlation was used to obtain the entire displacement field during testing. The crack propagation process and the strain localization were investigated, and the fracture toughness considering crack deflection was calculated using a modified two parameter model (MTPM). The results showed that extrusion-based specimens exhibited more deflected cracks, affirming the hypothesis that fiber alignment via extrusion influenced the crack propagation, thereby enhancing the fracture properties of the composite.