Overview
The Global Cement and Concrete Association (GCCA) India, in collaboration with the National Council for Cement and Building Materials (NCB), released a groundbreaking report titled "Carbon Uptake by Concrete" on the 63rd Foundation Day of NCB, celebrated on 26th December 2025. This study challenges conventional perceptions of concrete as merely a carbon emitter.
Key Findings
- Concrete absorbs atmospheric CO₂ throughout its lifecycle through natural carbonation
- Acts as a passive carbon sink, particularly effective under Indian climatic conditions
- The cement sector contributes approximately 7% of total global anthropogenic CO₂ emissions
- Despite emissions, concrete's carbon absorption capacity is significantly underreported
Carbonation Process Explained
- Atmospheric Interaction: CO₂ from air penetrates concrete surfaces over time
- Chemical Reaction: CO₂ reacts with calcium hydroxide (Ca(OH)₂) in concrete
- Calcium Carbonate Formation: Produces calcium carbonate (CaCO₃), effectively sequestering carbon
- Lifelong Process: Continues throughout the structure's operational life and beyond
Report Recommendations
- Accurate Carbon Accounting: Develop precise methods to measure concrete's carbon absorption
- Improve Data Quality: Enhance robustness of data collection on concrete usage and exposure conditions
- Refine Estimation Methods: Create India-specific models for national carbon inventories
- Policy Integration: Recognize concrete's role in sustainable construction policies
Industry Context
Classified as a hard-to-abate industry, the cement sector faces unique decarbonization challenges. This report offers a nuanced perspective by highlighting concrete's dual role. Under Indian climatic conditions—characterized by high temperatures and humidity—carbonation occurs more rapidly, making Indian concrete structures particularly effective carbon sinks.