Alkali-silica reactions (ASR) in concrete dams – field survey, ND-testing and laboratory analyses

The main scope of the Norwegian R&D project "Excon" (2023-2025) is to contribute to extending the surface life of important concrete infrastructure and developing a decision-making tool that considers both economic and environmental factors. A sub-aim is developing innovative methods for non-destructive field survey, monitoring, and laboratory analysis of cored samples. Moreover, a review of methods for the repair of concrete structures with Alkali-Silica Reactions (ASR) is also part of the project, with a focus on concrete dams. The project is mainly financed by the Norwegian Research Council, with supplementary funding and in-kind work from many industrial partners. In the first part of the project, a review report on methods for non-destructive testing and monitoring was prepared. During 2024, some of these methods have been applied to selected case structures, among them three concrete dams. The focus was placed on monitoring of cracking caused by ASR. In addition to the “Cracking Index” (CI) method, crack detection by use of photogrammetry and advanced NDT measurements (ultrasound scanning) was also performed. One aim was to assess the accuracy of using those tools for the measurement of the extent of cracking. From all dams, samples were cored for laboratory analysis; Stiffness Damage Testing (SDT) for all dams, and microstructural analysis for Dam I.