The use of X-ray microtomography to investigate the shear behavior of hybrid fiber reinforced strain hardening cementitious composites

Abstract

This paper presents an experimental investigation on the shear response of strain-hardening cement-based composites (SHCC) using X-Ray microtomography (microCT). For the developed composites, PVA and micro steel fibers were used in a constant fiber volume fraction of 2.0 %. The hybrid composites were produced replacing PVA by steel fibers in 25 %, 50 % and 75 % fractions. The shear behavior of the composites was studied by performing Iosipescu shear tests. The crack pattern evolution along the tests and the displacement field in the notch region were analyzed using the Digital Image Correlation (DIC) technique. Information about the porosity, fiber distribution and alignment were obtained using microCT for each specimen tested . The results show that the hybridization increases the crack opening but has little effect on the shear strength. The results also show that PVA fibers affect the alignment of the steel fibers and increase the porosity of the composites. • PVA fibers increase the porosity and affect the alignment of steel fibers. • The inclusion of steel fibers increases the crack opening. • Steel fibers tend to concentrate in the notch region. • The largest pores do not affect the cracks pattern in the notch region.