Experimental study of static and dynamic behavior of concrete under high confinement: Effect of coarse aggregate strength

Abstract

This article focuses on the static and dynamic behavior of two concretes under very high pressure loaded at different strain rates. Concretes differ by the type of coarse aggregates (limestone or siliceous). Specimens are confined in an elastic steel ring, insuring a quasi-uniaxial strain state of loading during axial compression, the so-called quasi-oedometric compression (QOC) tests. The effect of the loading path is first investigated by comparing their response under static QOC tests to triaxial compression results. Compaction of concrete made with strong siliceous aggregates is much higher in QOC test than in triaxial compression test, contrary to concrete made with soft limestone aggregates. Both concretes are then subjected to Split Hopkinson Pressure Bar testing. At high strain rate volumetric stiffness and deviatoric strength of both concretes are increased. Moreover, the increase of concrete strength with strain rate is more pronounced for concrete made with limestone aggregates than with siliceous aggregates.