Determining of the possible carbonation and depth mesure of a hardened concrete sample

Determining of the possible carbonation and depth mesure of a hardened concrete sample.

Portland cement concrete initially has a basic character medium (with a pH ≥ 12). In these conditions the steel of the reinforcement is passivated and can not suffer corrosion as a consequence exclusively of humidity. With the passage of time and as a consequence of the reaction of the portlandite with the environmental CO2, this pH goes down to values lower than 9. In this situation, this concrete no longer protects the steel against corrosion and in case there is enough humidity, it will appear with the usual associated lesions.

To assess the change in pH, an indicator is applied to a recent break with an atomizer (dissolution of phenolphthalein in 1% alcohol).

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