In the relentless pursuit of sustainability, the construction industry is increasingly turning to innovative solutions to mitigate its carbon footprint. A groundbreaking study led by David Bastos from the Sustainable Construction Materials Association (c5Lab) in Portugal has shed new light on how recycled aggregates (RAs) can play a pivotal role in carbon capture and storage. The research, published in the journal ‘Applied Sciences’ (translated to ‘Aplicadas Ciências’), delves into the intricate dance of temperature, humidity, and CO2 concentration in forced carbonation reactions, offering a roadmap for industrial implementation.
Bastos and his team focused on the carbonation of recycled aggregates, a process where CO2 reacts with calcium hydroxide in cement-based materials to form calcium carbonate. This reaction not only strengthens the aggregates but also sequesters CO2, a significant step towards reducing greenhouse gas emissions. “The potential of recycled aggregates in carbon capture is immense,” Bastos asserts. “By optimizing the carbonation process, we can enhance material properties and contribute to environmental sustainability.”
The study, conducted under conditions mimicking those found in cement plant chimneys, revealed that temperatures around 60°C and CO2 concentrations around 25% accelerate the carbonation reaction and increase CO2 absorption. Relative humidity also played a crucial role, with a reduction from 60% to 40% leading to decreased CO2 absorption. The highest CO2 capture was achieved by a recycled concrete aggregate at 23°C, 60% relative humidity, and 25% CO2 concentration.
These findings are not just academic exercises; they hold substantial commercial implications for the energy and construction sectors. By identifying the optimal conditions for CO2 sequestration, industries can enhance the efficiency of carbon capture processes, potentially reducing operational costs and environmental impacts. “This process can help mitigate the environmental impacts of cement production and increase the likelihood of achieving carbon neutrality targets by 2050,” Bastos explains.
The research also underscores the importance of a circular economy, where construction and demolition waste are repurposed rather than discarded. This approach not only conserves natural resources but also adds value to waste materials, aligning with global sustainability goals.
As the construction industry grapples with the challenges of decarbonization, studies like Bastos’ offer a beacon of hope. By leveraging the power of recycled aggregates and forced carbonation, the sector can move closer to achieving carbon neutrality. The journey from laboratory to industrial implementation is fraught with challenges, but the potential rewards—both environmental and commercial—are immense. As Bastos and his team continue to push the boundaries of sustainable construction, the future of the industry looks increasingly green.