Question
What is the Phenolphthalein Test?
Expert Answer
The Phenolphthalein Test is the standard method for determining the depth of carbonation in concrete. We spray a solution of phenolphthalein onto a freshly broken concrete surface or drill core. Non-carbonated (alkaline) concrete turns bright pink. Carbonated (acidic) concrete remains colorless. Measuring the depth of the colorless layer tells us if the carbonation has reached the reinforcement steel.
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MPS Concrete Solutions delivers structural concrete repair across London and the UK — covering spalling, carbonation treatment, rebar restoration, resin injection, and crack repair for commercial and infrastructure clients.
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