Dynamic compressive impact tests of building sandstone with a large split hopkinson pressure bar

Abstract

The uniaxial compression behavior of building sandstone at high strain rates is not well understood. In this study, standard and flattened cylinders were fabricated for dynamic and static compression tests. A split Hopkinson pressure bar was employed to perform the impact tests at strain rates up to 93.2 s−1. The static compression strength of the flattened cylinders was 112.7 MPa, which was 50% higher than that of the standard cylinder. The fracture damage of the cylinder was closely correlated to the strain rate. Incomplete fragmentation appeared at low strain rates, whereas complete fragmentation appeared at a higher strain rate. Representative diagrams were developed using the characteristic points of the Type I and Type II diagrams, which were characterized by the rebounding and dropdown portions due to the strain rate level. The correlations between the dynamic strength, strain rate, and dynamic modulus were analyzed based on the experimental results. The dynamic increase factor (DIF) was overestimated when the static compressive strength of the standard cylinder was used. A two-portion expression for DIF was developed in accordance with the experimental data. The energy absorption density was proportional to the strain rate and dynamic strength. Two mathematical expressions were obtained based on the experimental energy absorption density, characterized by the experimental peak stresses. The present study is valuable for evaluating the dynamic behavior of sandstone under extreme loads.