The Potential of 3D Printed Concrete for Carbon Capture

Scientists at Nanyang Technological University, Singapore (NTU Singapore) have developed a 3D concrete printing technique that captures carbon, offering a new way to reduce the environmental impact of the construction industry.

This research, published in Carbon Capture Science & Technology, introduces a method to lower the carbon footprint of cement production, which is responsible for 1.6 billion metric tons of CO₂, or 8 % of global CO₂ emissions.

The technology works by incorporating steam and CO₂, captured from industrial processes, directly into the concrete. This approach reduces material usage, construction time, and labor requirements, offering potential benefits for both sustainability and efficiency.

Compared to traditional 3D printed concrete, this method enhances the concrete’s mechanical properties, increasing its strength through the injection of CO₂ and steam.

The building and construction sector causes a significant portion of global greenhouse gas emissions. Our newly developed 3D concrete printing system offers a carbon reducing alternative by not only improving the mechanical properties of concrete but also contributing to reducing the sector’s environmental impact. It demonstrates the possibility of using CO₂ produced by power plants or other industries for 3D concrete printing. Since traditional cement emits a lot of carbon, our method offers a way to plough back CO₂ through 3D concrete printing.

Tan Ming Jen, Professor, School of Mechanical and Aerospace Engineering, Nanyang Technological University

The research team believes their innovation could help meet global sustainability goals and reduce the construction industry's reliance on energy-intensive processes, such as reinforced concrete construction.

This advancement builds on previous 3D printing research by Professor Tan and his team at NTU’s SC3DP, in collaboration with partners at Aramco.

Improved Printability, Increased Strength, and More Carbon Captured

The research team developed a 3D concrete printing system by connecting the printer to CO₂ pumps and a steam jet.

When activated, the system introduces CO₂ and steam into the concrete mix as the structure is printed. The CO₂ combines with the concrete components to form a solid that is captured and stored, while the steam improves the material’s ability to absorb CO₂, enhancing the properties of the 3D printed structures.

In laboratory testing, the researchers found that the concrete’s printability improved by 50 %, enabling more efficient shaping and printing.

Additionally, the printed structures exhibited greater durability and strength. Compared to standard 3D-printed concrete, the new concrete was up to 35.8 % stronger in compression (the amount of weight it can support) and 45.3 % stronger in bending (the amount of flex it can withstand before breaking).

Notably, this technique is also more environmentally friendly than conventional 3D printing methods, as it absorbs and stores 38 % more carbon dioxide.

We are at a critical time where the world is accelerating efforts to meet climate change targets. We believe our technology could contribute to making the construction industry more sustainable.

Lim Sean Gip, Study First Author and PhD Student, School of Mechanical and Aerospace Engineering, Nanyang Technological University

Study Co-Author, Dr. Daniel Tay, a Research Fellow from NTU School of MAE, said, “Our proposed system shows how capturing carbon dioxide and using it in 3D concrete printing could lead to stronger, more eco-friendly buildings, advancing construction technology.”

NTU and Aramco have jointly submitted a U.S. patent application for the innovation. The researchers plan to use waste gases instead of pure carbon dioxide in their studies and aim to optimize the 3D printing technique for greater effectiveness.

Video Credit: Nanyang Technological University

Journal Reference:

Lim, S. G., et. al. (2024) Carbon capture and sequestration with in-situ CO₂ and steam integrated 3D concrete printing. Carbon Capture Science & Technology. doi.org/10.1016/j.ccst.2024.100306