Experimental study of biaxial compressive damage behaviour of concrete at different strain rates

Reported herein are the results of biaxial dynamic compressive tests on plain concrete specimens that were carried out on a static–dynamic triaxial test system, with strain rates ranging from 10–5 to 10–2 s–1. The effects of strain rate on dynamic strain–strain curves, dynamic compressive strengths, initial elastic moduli and critical strains of concrete are studied. Test results demonstrate that the biaxial compressive strength and the initial tangent modulus of concrete increase with increasing strain rate, but the critical strain of concrete decreases with increasing strain rate. Also, the effects of strain rate on the damage threshold stress and strain of concrete are studied. On the stress space, the damage threshold stress of concrete increases with the increase in strain rate, while its ratio to the ultimate strength is independent of the strain rate. On the strain space, the damage threshold strain of concrete and its ratio to the critical strain are independent of the strain rate.