Influence of the concrete moisture content on the strain development due to cyclic loading

Abstract

Due to research activities on the topic of concrete mixtures during the last decades, concrete compressive strength has increased significantly. At the same time, the lifespan of concrete structures has continuously extended. Therefore, the fatigue behaviour of High-Performance Concrete (HPC) becomes more important in regard of service life design. Previous studies on concrete prove that the number of cycles to failure due to pure compressive cyclic loading mainly depends on frequency and amplitude. By conditioning the humidity of high-performance concrete test specimens, a significant change of the number of cycles to failure can be determined. The strain development is considered as a good damage indicator and provides reliable information about the current damage development. It is known that the strain development depends on different factors such as maximum stress level. As moisture has a significant influence on the number of cycles to failure, the strain development was examined in more detail. Experiments of HPC with three different concrete moisture contents were investigated. For this, different types of storage were used to achieve the different moisture levels. The focus is on the strain development. This will be used to investigate in more detail why the fatigue resistance of moist concrete is lower than that of dried concrete. Therefore, the moisture content and the maximum stress level were varied.