Topic: Environment
Scientists at the ILL used neutron imaging to study how water affects CO₂ storage in recycled concrete. They found that carbonation reshapes the material and creates cracks, but also locks CO₂ in mineral compounds. This discovery can help reduce construction's environmental impact.
The construction sector is a major contributor to global waste and greenhouse gas emissions. One way to address this issue is through accelerated carbonation of recycled concrete. This process involves exposing crushed recycled concrete to CO₂-rich gas, allowing the carbon dioxide to react with the old cement paste and become locked into stable mineral compounds.
But there's a problem: concrete doesn't behave like a simple sponge for CO₂. The reaction depends on a delicate balance between gas, water, pores, and minerals. If the pores are too dry, carbonation slows down. If they contain too much water, CO₂ struggles to move through them.
Researchers at the ILL used neutron imaging to study this process in real-time. They found that carbonation actively reshapes the material as it progresses: releasing water, changing the pore network, slowing CO₂ transport, and creating cracks that later partly close. This discovery provides a clearer picture of what controls CO₂ storage in recycled concrete.
Concrete is everywhere – in buildings, roads, bridges, tunnels, and almost every form of infrastructure. Its environmental impact, however, is considerable: cement production is responsible for 5%–7% of global CO2 emissions. The construction sector also generates vast quantities of concrete waste, which could become a resource if reused and potential CO₂ capture within a circular recycling framework.
Between 2.8 and 5.1 gigatonnes of concrete may be available annually for reuse and potential CO₂ capture. This creates a double challenge: reducing the construction sector's carbon footprint while reusing large quantities of concrete waste.
Why It Matters
This discovery can help India reduce its greenhouse gas emissions by promoting sustainable construction practices. By turning old concrete into a carbon trap, we can mitigate climate change and create a more circular economy.
Key Facts
- The construction sector is responsible for 5%–7% of global CO2 emissions.
- Between 2.8 and 5.1 gigatonnes of concrete may be available annually for reuse and potential CO₂ capture.
- Accelerated carbonation of recycled concrete can help reduce the environmental impact of construction while giving demolition waste a second life.
- Neutron imaging was used to study how water affects CO₂ storage in recycled concrete.
- The ILL researchers found that carbonation reshapes the material, releases water, and creates cracks.
Key Terms
- Accelerated Carbonation
- A process that involves exposing crushed recycled concrete to CO₂-rich gas to lock CO₂ in mineral compounds.
- Neutron Imaging
- A technique used to study the internal structure of materials by bombarding them with neutrons and measuring the scattered radiation.
Implications
This discovery can help India reduce its greenhouse gas emissions by promoting sustainable construction practices. By turning old concrete into a carbon trap, we can mitigate climate change and create a more circular economy.
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