ABSTRACT

The development of the construction industry moves towards resource-saving and filigree constructions. Ultra-high performance concrete (UHPC) was developed to reach a higher efficiency of the material usage. As a result, the structures will be leaner and lighter. However, due to reduction of self-weight through the optimized use of materials, structures are more susceptible to induced vibrations. This is particularly important to structures under cyclic loading, such as long-span bridges and wind turbines, which are exposed to very high load cycles. A thorough understanding of the fatigue behaviour of UHPC is thus required. The focus of the project “load-induced increase of temperature in UHPC” is to study the mechanism of heat-generation in concrete members due to cyclic loading and its influence on the fatigue behaviour of concrete. The hypothesis is that the induced temperature fields and the resulting concrete stresses have a non-negligible influence on the damage process and the fatigue strength of UHPC. The investigation focuses on the influence of the frequency and regime of load on the temperature development in concrete during the fatigue process. A systematic experimental study within three different testing frequencies and maximum compressive stress levels is carried out. The surface and inner temperature as well as the longitudinal and transverse strain of the specimens are measured continuously. In this paper, the main results of measurement are presented and discussions on the development of load-induced temperature of concrete are also given.