Influence of concrete humidity on the temperature development under fatigue compressive loading

Abstract

Due to research activities on the topic of concrete mixtures during the last decades concrete compressive strength could be increased significantly. At the same time the lifespan of concrete structures has been continuously extended. Therefore, the fatigue behavior of modern High Performance Concrete (HPC) becomes more important with respect to service life. Previous studies on normal strength concrete have shown that the number of cycles to failure under pure compressive cyclic loading mainly depends on frequency and amplitude. An increase of the loading frequency leads to a higher number of load cycles to failure. Recent research work shows that the humidity of the specimen is also influencing the fatigue behavior of concrete. Conditioning of the test specimen to high humidity led to significant lower fatigue life. Other research activities on high strength concrete point out the effect of the loading frequency on load induced heat effects of the concrete. The experimental study presented here aims on the influence of the humidity on the temperature development under fatigue compressive loading and on the number of cycles to failure. It comprises three fatigue test series at a test frequency of 10 Hz with sealed cylindrical specimens of the same concrete with different degrees of humidity. In addition, destructive and non-destructive tests were carried out on damaged and undamaged concrete.