Carbonation

Introduction

Carbonation is one of the most common causes of reinforcement corrosion in concrete structures.
When carbon dioxide (CO₂) from the atmosphere penetrates concrete, it reacts with calcium hydroxide and reduces the concrete’s alkalinity — creating conditions that allow steel reinforcement to corrode.

At  ASSOCIATED TESTING LABORATORIES, we provide accurate and reliable Carbonation Testing to assess the depth of carbonation and determine the durability and remaining life of concrete structures.

What is Carbonation in Concrete?

Carbonation is a chemical reaction between carbon dioxide in the air and the hydrated cement compounds inside concrete.
This reaction lowers the pH of concrete from around 12.5 to below 9, reducing its natural protection against steel corrosion.

As carbonation progresses deeper into the concrete, it can eventually reach the reinforcement, leading to:

• Corrosion of steel

• Cracking and spalling

• Reduction in structural strength

• Long-term deterioration

Why is Carbonation Testing Important?

Carbonation testing helps identify:

• Whether reinforcement is at risk of corrosion

• The rate and extent of deterioration

• Durability and life expectancy of concrete

• Need for repair, rehabilitation, or protective coatings

• Quality of concrete in old and exposed structures

How Carbonation Test is Done

We perform carbonation testing as per IS 516, IS 1193, and standard global procedures.

Testing Procedure:

1. A small freshly exposed surface of concrete is prepared using drilling or breaking.

2. A 1% phenolphthalein indicator solution is sprayed on the surface.

3. The solution colors non-carbonated concrete (alkaline) to pink.

4. Carbonated concrete remains colorless.

5. The depth of the colorless layer is measured as carbonation depth.

Factors Influencing Carbonation

Our reports consider key factors such as:

• Concrete quality and strength

• Water–cement ratio

• Age of the structure

• Exposure to rain, humidity, and CO₂ levels

• Cracks or poor cover

• Surface finishing

This ensures accurate interpretation and suitable recommendations.

Applications of Carbonation Test

Carbonation testing is widely used for:

• Structural audits

• Repair and rehabilitation planning

• Bridges, buildings, tunnels, and flyovers

• Old concrete structures

• Coastal and industrial environments

• Quality evaluation of existing concrete

Benefits of Carbonation Testing

• Detects early signs of corrosion risk

• Assesses concrete durability

• Helps plan maintenance and repair

• Cost-effective and simple testing method

• Provides clear visual results

Our Carbonation Testing Services

At  ASSOCIATED TESTING LABORATORIES, we offer:

• On-site carbonation depth testing

• Advanced structural audit services

• Combined assessment with Half Cell Potential, UPV & Rebound Hammer

• Detailed technical reporting with expert recommendations

• Compliance with IS, ASTM, and BS standards

Why Choose Us?

• Certified NDT & structural engineers

• Accurate testing with standard procedures

• Fast reporting with detailed analysis

• Modern equipment and professional team

• Affordable, reliable & high-quality service