Transient creep of concrete under biaxial stress and high temperature

Understanding concrete behavior under transient high temperature is an important aspect of structural fire research. Consequently, many investigations have been performed under uniaxial loading conditions, but, only a few under biaxial states of stress. This report has two primary goals. The mechanical behavior of unsealed concrete and mortar was studied under biaxial stresses and transient temperature. Furthermore, the influence of the concrete composition was investigated for quartzitic concrete and mortar in thermal expansion tests and biaxial transient creep tests. Based on the test results a model of the transient creep of concrete under multiaxial loading is proposed. In combination with a suitable high temperature failure model, this model is applicable for concretes with different compositions.