Petrographic Atlas: Characterisation of Aggregates Regarding Potential Reactivity to Alkalis

Abstract

Since deleterious alkali-silica reaction (ASR) in concrete was recognised for the first time in the 1940s, research has been developed in order to identify and understand the phenomena, materials, and mechanisms involved. ASR is a complex chemical reaction still not fully understood, involving alkalis dissolved in the concrete pore fluid and some forms of reactive silica when enough humidity is available. Deleterious ASR involves expansion within hardened concrete and thereby induces extensive cracking, providing easy access of the environment to the concrete interior, thus enabling physical deterioration mechanisms to accelerate overall structural decay