Date of Award
Open Access Dissertation
Civil and Environmental Engineering
Alkali-silica reaction (ASR) is a chemical reaction, which causes damage in concrete structures such as bridges, dams, and nuclear containments and powerplant structures. The ASR-induced damage may endanger the integrity and serviceability of structures. Several methods such as visual inspection, petrographic analysis, demountable mechanical strain gauges, and cracking index have been utilized for study the effect of ASR on structures, which are not always efficient in early damage detection and some are destructive and prohibited in nuclear structures. Nondestructive methods and structural health monitoring techniques can be alternatives for the condition assessment of structures. Among the nondestructive methods, acoustic emission (AE) is preferable due to high sensitivity of AE sensors, source localization ability, and sensing capability in one-side-access structures. The goal is the condition assessment of structures affected by ASR using AE. Therefore, in the current research, data-driven methods in combination with signal processing techniques are employed to find a potential temporal trend in the AE data and relate the trend to the damage progression caused by ASR. In addition, the effect of stress boundary condition on the ASR-induced damage distribution and its reflection on the AE data is investigated. Damage contours based on AE data are developed and utilized to compare event distributions though the medium-scale specimens with different confinements and investigate the temporal evolution of the distributions. Furthermore, the efficacy of differing information entropy calculation approaches for concrete structures undergoing Alkali-Silica Reaction (ASR) induced damage is investigated.
The results of the studies indicate that confinement affects the distribution of AE events. In the confined specimen, the distribution of AE events in the mid-width region of the specimen is concentrated and has a sharp peak. However, in the unconfined specimen, the distribution of AE events is more uniform, and cracks are randomly distributed.
The entropy results show that the randomness of events increases at the earlier stage of ASR, which is expected due to the microcrack formation and decreases at the later stage due to the formation of macrocracks.
The overall outcome in this dissertation demonstrates the potential of using AE for condition assessment of concrete structures affected by ASR degradation. However, more research is required to standardize the method for the field application.
Soltangharaei, V.(2020). Evaluation of Temporal Damage Progression in Concrete Structures Affected by ASR Using Data-driven Methods. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/6080