How we should control ASR in new concrete or precautionary measures?

ASR (Alkali-Silica Reaction)

Oxides of alkali in minor amount present in cement, while in Aggregate or sand their exist alkali oxides that can be unsuitable environment for concrete.

² Oxides of Sodium & Potassium in cement is a minor amount, that react with silica to form Alkali-Silica gel

² Alkali-Silica gel of unlimited swelling type under favourable conditions of moisture and temperature in voids and create cracks and further it causes disruption and pattern cracking.

Alkali-silica reaction can be controlled using certain supplementary cementitious materials. In-proper proportions, silica fume, fly ash, and ground granulated blast-furnace slag have significantly reduced or eliminated expansion

Deleterious asr can be prevented solely by limiting the alkali content of the concrete. The threshold alkali content primarily depends on the reactivity of the aggregate and whether or not the concrete is exposed to alkali compound in service. Also, asr can be prevented by using supplementary cementing material SCM or a combination of SCMs.