Development of a large-scale torsional split Hopkinson tube for dynamic shear test of mortar material

Due to the lack of reliable dynamic shear test technology, there are few studies on dynamic pure shear performance of concrete materials. Based on the one-dimensional stress wave propagation theory, a large-scale torsional split Hopkinson Tube (LTSHT) with an outer diameter of 110 mm was developed. The LTSHT comprises a bearing system, an axial driving system, a four-lug symmetrical impact loading system, an incident tube, and a transmission tube. Numerical simulations showed that the LTSHT produced a well-defined torsional wave, and the bending wave was very small when the lug-error was not more than 0.05 mm. Furthermore, a data measurement and processing of the LTSHT were proposed. Dynamic pure shear tests with shear strain rate similar to 14 s(-1) on three thin-walled mortar specimens were conducted. The failure process was recorded. The dynamic shear strength was similar to 8 MPa and shear stress-strain curves of the three thin-walled mortar specimens showed great repeatability.