Carbonation testing is a diagnostic method used to measure the depth of carbonation in concrete and assess the risk of reinforcement corrosion.
Explanation
The most common method involves removing a small concrete sample and applying a phenolphthalein indicator solution. Uncarbonated concrete turns purple due to its high alkalinity, while carbonated areas remain colourless.
By measuring the carbonation depth and comparing it to the concrete cover over reinforcement, specialists can determine whether steel protection has been compromised.
Carbonation testing is typically carried out during condition surveys of:
- Car parks
- Residential buildings
- Balconies
- Commercial structures
- Ageing reinforced concrete assets
It is often combined with cover surveys and corrosion assessment.
Why It Matters
Without testing, repair strategies may be mis-specified.
Carbonation testing helps:
- Identify corrosion risk
- Determine extent of required breakout
- Inform coating selection
- Prevent premature repair failure
Accurate diagnosis ensures targeted, cost-effective remediation and long-term durability.