Monitoring of an hydraulic structure affected by ASR: A case study

Relevant and effective instruments and techniques must be selected for monitoring hydraulic structures affected by Alkali-Silica Reaction (“ASR”). A program aiming at assessing the condition of a hydraulic structure affected by ASR is presented in this paper. The structure has been exhibiting signs of ASR for more than 30 years and shows various levels of damage. The program encompassed different components, consisting of: (1) stress measurement, (2) evaluation of concrete condition by nondestructive methods without drilling (seismic tomography), (3) the evaluation of the mechanical, physical and petrographic properties of the concrete determined from cores recovered from full-length boreholes. The results of this case study suggest that ASR may generate relatively little damage in structures and that the concrete mechanical properties do not seem to be significantly affected despite high expansion levels measured in this structure. A major crack was localized with the seismic tomography. The monitoring program will be used to follow the development of ASR in the structure.