Concrete Hydraulic Structures Affected by Alkali–Aggregate Reaction: Numerical and Experimental Investigations

Abstract

An existing hydroelectric facility affected by alkali–aggregate reaction (AAR) is considered in this study through numerical and experimental investigations. A new developed phenomenological hygro–chemo–mechanical approach for AAR is presented and is shown to be practical and effective in damage assessing of large-scale hydraulic concrete structures. Experimental investigations were conducted to characterize the AAR kinetics of mass concrete mixture with very large aggregates, used in the construction of the facility. By combining experimental, numerical, and monitoring investigations, it was possible to assess size effects related to the free AAR expansion of mass concrete. Numerical simulations allowed to obtain a damage pattern similar to the cracking profile of the existing facility, to provide mechanical interpretation of the jumps observed in the instrumentation data, and most importantly, to predict the remaining time before reaching the asymptotic expansion of the facility: a very important result for owners of hydroelectric facilities affected by AAR.