ASR is caused by a reaction between free alkalinity in the concrete pore solution and reactive forms of silica in the aggregate. This reaction forms an alkali-silicate gel which with the availability of moisture increases in volume, exerts expansive pressure and results in cracking of the concrete. Three conditions are necessary for ASR and the resultant cracking to occur in concrete –
- 1. A sufficiently high alkali content of the cement pore fluid.
- 2. A reactive aggregate.
- 3. Moisture – either as liquid or vapour is needed to cause the gel to expand.
AQURON Concrete Treatments – The Background
AQURON is a colloidal silicate solution that reacts with calcium hydrates (free alkali) and moisture in the pores of mature concrete to form a calcium-silicate-hydrate (C-S-H) gel within the pores. The reaction continues deep (>100mm) into the cover concrete and produces a permanent, flexible, pore-blocking hydrogel.
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More information: AQURON 7000 Concrete Treatment – The Solution for ASR
Read more on the hidden threat of ASR.