Influence and Revision of Transverse Inertia Effect and Pressure Hardening Effect on Strain-Rate Hardening Effect of Compressive Strength of Concrete

The compressive strength of concrete has a significant strain-rate hardening effect under a high strain-rate loading. However, some problems, such as transverse inertia effect, should be considered even if all conditions in the test process are perfect. And the strain-rate effect and pressure hardening effect are decoupling, so the part of dynamic increase factor which is on account of the increase of pressure must be excluded. Based on previous investigation results, the transverse inertia effect and pressure hardening effect were studied through theoretical analysis and numerical simulation and the true strain-rate effect of concrete was obtained. The study results show that with the increase of the radial size and strain-rate of the specimen, the decrease of sound velocity and the fracture strain of concrete material, the transverse inertia effect is more and more obvious. Compared with the concrete specimen, the strain-rate effect of concrete material is much smaller. Concrete material is a kind of structural material which contains a mass of micro-void and randomly distributed initial damage, so it should be a strain-rate hardening material.