DIAGNOS-AAR – Diagnose der Alkali-Aggregat-Reaktion in Staumauern (State-of-the-Art Bericht)

• Research unit: SFOE
• Project number: SI/500863

Final report (English)

In the alkali-aggregate reaction (AAR) minerals present in aggregates react with the alkaline pore solution of the concrete (pH 13.0–13.5). The term AAR includes the reaction with silica, silicates and carbonates. In this report AAR relates to the reaction with silica and silicates. The reaction with carbonates is denoted specifically as alkali-carbonate reaction (ACR). As the AAR product takes up water, stress is generated that can lead to expansion and cracking of concrete. Typically, such cracks are formed years or even decades after the affected structures were built. Any type of concrete structures can be affected, provided three prerequisites are present: (1) sufficient alkalinity of the pore solution, (2) reactive minerals in the aggregates and (3) a sufficient moisture level. AAR is one of the most important deterioration mechanisms in concrete, leading to substantial damages of structures worldwide [e.g. Bérubé et al., 2000a; Tang & Deng, 2004; Broekmans, 2008; Thomas & Kwilosz, 2012].

Auftragnehmer/Contractant/Contraente/Contractor:
Empa – Laboratory for Concrete / Construction Chemistry

Autorschaft/Auteurs/Autori/Authors:
Leemann,Andreas
Griffa,Michele

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