Concrete in dynamic tension: The fracture process

The fracture properties of concrete are rate dependent. In this thesis the results on tensile tests at static, moderate and high loading rate are presented. The results show the influence of the loading rate not only the tensile strength, but also on the fracture energy, stress-defromation relation and fracture parameters, like fracture lengths and width of the fracture zone. The failure mechanisms are reconstructed and the dominant mechanisms behind the rate dependency are identified. By using basic principles of fracture mechanics and a simple model based on the Stefan effect, the loading rates at which the mechanisms have significant effect have been determined. The dominant mechanisms found in the research can be implemented in dynamic models and the acquired data set can be used to validate numerical models.