Abstract
The paper presents a testing facility, which enables the characterization of the shear behavior of cementitious composites under quasi-static and impact shear load. The device was designed by means of an extensive numerical parameter study on device geometry, materials and wave propagation, as well as specimen configurations and boundary conditions. The new shear testing device was integrated into a gravity-driven Split-Hopkinson tension bar (SHTB) for shear impact experiments and in a hydraulic testing machine for quasi-static shear experiments on strainhardening cement-based composites (SHCC). The shear response of the SHCC specimens was derived from the force obtained on the transmitter bar in the SHTB accompanied by high-speed optical measurements, which also enabled an accurate analysis of the crack-opening displacements and fracture modes by means of Digital Image Correlation (DIC).
Highlights
Strain-hardening cement-based composites (SHCC) are a class of fiber reinforced composites consisting of fine-grained cementitious matrices and short, randomly distributed micro-fibers in a volume fraction usually ranging between 1% and 2% [1]
The difference between the vertical deformation obtained for the sample and mode II crack opening displacement (COD) is due to the formation of the tensile cracks in both shear spans, prior to shear deformation
This can be seen in the failure process of the SHCC sample as obtained from Digital Image Correlation (DIC)
Summary
Strain-hardening cement-based composites (SHCC) are a class of fiber reinforced composites consisting of fine-grained cementitious matrices and short, randomly distributed micro-fibers in a volume fraction usually ranging between 1% and 2% [1]. The investigation of the shear behavior of SHCC in anti-symmetric flexural tests yields fracture resulting from both flexural and shear crack propagation despite purposefully optimized notch geometries [15] This makes the experimental derivation of the. The punch through shear testing techniques using the split-Hopkinson pressure bar (SHPB) do not enable an optical monitoring of the fracture modes [16][17] This disadvantage can be eliminated by using beam like specimens and suitable adapters such as in the strain energy frame impact machine (SEFIM) [18]. In this case the gripping and boundary conditions should be optimized for limiting the occurrence by flexural cracks and impose shear crack formation and fracture. Quasi-static and impact shear experiments were conducted on SHCC and the specimen responses were analyzed in terms of shear resistance and fracture mode
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