ABSTRACT
Concrete which is submerged in water shows a significantly lower fatigue resistance than that stored and tested in air. This phenomenon was recognized in the past, but which kind of water-induced damage mechanisms are involved in the degradation process is still unknown. Recent studies have led to the question: How does the water in the microstructure of the cement stone influence its fatigue resistance? Well-instrumented fatigue tests on high-strength concrete specimens which were stored under different moisture conditions were executed. The first results show a strong dependence of the fatigue resistance on the amount of water in the microstructure of the concrete. The influencing effect of the water is investigated by analyzing the number of cycles to failure, the development of stiffness and the acoustic emission over the degradation process of the concrete.
