Dynamic Triaxial Compression Experiments on Cor-Tuf Specimens

Abstract

A set of dynamic triaxial compression experiments at 50, 100, and 200 MPa confinement have been conducted with a modified Kolsky bar on cylindrical ultra-high strength concrete Cor-Tuf specimens of diameter 19 mm and length of 12.7 mm. The modified Kolsky bar utilized is capable of performing a triaxial compression test with a dynamic loading for a confining pressure of up to 400 MPa on specimens with 19.05 mm diameters. The experiment is composed of a hydrostatic phase which occurs at a quasi-static strain rate followed by a dynamic shear phase which occurs at a high strain rate. A set of 28 experiments were conducted at strain rates of 100 and 200 s−1. The experiments show that the fracture strength of the material increases under increasing pressure. The specimens showed higher strength in the dynamic confined experiments than both the quasi-static TXC experiments and the unconfined-uniaxial dynamic tests. The strength increase was in part caused by specimen size difference. Although the trend towards brittle ductile transition is observed the specimens were not loaded in a high enough confinement for the phase change to occur.KeywordsDynamic confinedModified Kolsky barSplit-Hopkinson pressure barTriaxial compressionCor-Tuf