Author: D. Klausen

Publisher:

Published: 1980

Total Pages: 10

ISBN-13:

Frequently changing stresses beyond the fatigue limit give rise to material damage. It is assumed that the individual damages of each cycle are accumulated and thus lead to material fatigue. The lifetime of concrete for variable cyclic compressive loadings can be estimated with the help of the linear "cumulative damage hypothesis," if the stress is significantly beyond the assumed fatigue limit. It is not known in which way a stress below the fatigue limit influences the material's lifetime. Furthermore, for concrete up to 109 cycles to failure, a significant fatigue limit cannot be established. Due to the required high numbers of cycles a direct clarification by fatigue tests is not possible. Therefore, characteristic values have been determined which describe the development of damage dependent on the degree and frequency of the cyclic compressive load. For this purpose the "acoustic emission analysis" has been applied as well as the direct measured volume alteration method. Thereafter it has been determined if there is a relation between these values and the material lifetime and if statements on the fatigue limit of the concrete can be made.