Effects of load histories on dynamic biaxial compressive damage behaviours of concrete

The paper reports the results of biaxial dynamic compressive tests on plain concrete specimens that have undergone a loading history of 0, 30, 50 and 75% of biaxial compressive ultimate strength, carried out on a static–dynamic multiaxial test system, with strain rates ranging from 10−5/s to 10−2/s. The effect of load histories on dynamic stress–strain curves, dynamic compressive strengths, initial elastic moduli and critical strains of the concrete are studied. Test results demonstrate that the biaxial compressive strength and the biaxial critical strain of concrete decrease with the increasing loading history at the same strain rate, but the biaxial initial tangent modulus of concrete is independent of the load history at the same strain rate. Also, the effects of load histories on the biaxial damage threshold stress and strain of concrete in the stress and strain space are studied.