Scientists Transform CO2 Into Super-Strong 3D Printed Concrete

Scientists have developed a new 3D concrete printing method that captures carbon, enhancing the material’s strength and sustainability.

This innovation significantly reduces the construction sector’s carbon emissions by incorporating CO₂ directly into the concrete, promising a greener future for construction technologies.

Innovative 3D Concrete Printing

Researchers at Nanyang Technological University, Singapore (NTU Singapore) have created a 3D concrete printing method that captures carbon, offering a new way to reduce the construction industry’s environmental impact.

Detailed in the journal Carbon Capture Science & Technology, the technique targets cement’s significant carbon footprint. Cement production accounts for about 1.6 billion metric tonnes of carbon dioxide (CO₂) annually — around eight percent of global CO₂ emissions. The new method aims to lower emissions by reducing material usage, speeding up construction, and cutting labor needs.

Enhancing Concrete with Carbon Capture

The process works by injecting steam and CO₂ — captured as by-products from industrial processes — into the concrete mix during printing. This allows the concrete to trap and store CO₂ within its structure.

Tests showed that this method not only stores carbon but also strengthens the concrete. The printed material demonstrated greater mechanical strength compared to conventional 3D-printed concrete.

Advancements in Concrete Printing Technology

Principal investigator of the study, Professor Tan Ming Jen from NTU School of Mechanical and Aerospace Engineering (MAE), and NTU’s Singapore Centre for 3D Printing (SC3DP), said, “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 plow back CO₂ through 3D concrete printing.”

The research team believes their innovation represents a promising contribution towards achieving global sustainable development goals and reducing the industry’s reliance on conventional energy-intensive processes like reinforced concrete construction.

The new development builds on previous 3D printing for construction research by Prof Tan and his team at NTU’s SC3DP, as well as international collaborators.

Advancements in Printing and Material Strength

To develop their 3D concrete printing system, the research team connected the 3D printer to CO₂ pumps and a jet that sprays steam.

When activated, the system pumps CO₂ and steam into the concrete mix as the structure is printed. CO₂ reacts with the components in the concrete, turning into a solid form that stays locked inside the material (sequestered and stored). At the same time, steam improves the absorption of CO₂ into the 3D-printed structure, enhancing its properties.

Lab Results Demonstrate Significant Improvements

In lab tests, researchers found the printed concrete structure showed a 50 percent improvement in printability – meaning it can be shaped and printed more efficiently.

The structure also displayed better strength and durability. The printed concrete was up to 36.8 percent stronger in compression (how much weight it can bear) and up to 45.3 percent stronger in bending (how much it can flex before breaking) compared to regular 3D-printed concrete.

Notably, the method is also greener, absorbing and trapping 38 percent more carbon dioxide compared to traditional 3D printing methods.

A Greener, Stronger Future for Construction

First author Lim Sean Gip, PhD candidate from NTU School of MAE, said, “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.”

Co-author, Dr. Daniel Tay, 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.”

A US patent application for the innovation has been filed jointly by NTU and collaborators. In future research, the researchers plan to optimize the 3D printing process to make it even more efficient and potentially use waste gases instead of pure carbon dioxide.

Reference: “Carbon capture and sequestration with in-situ CO2 and steam integrated 3D concrete printing” by Sean Gip Lim, Yi Wei Daniel Tay, Suvash Chandra Paul, Junghyun Lee, Issam T. Amr, Bandar A. Fadhel, Aqil Jamal, Ahmad O. Al-Khowaiter and Ming Jen Tan, 26 September 2024, Carbon Capture Science & Technology.
DOI: 10.1016/j.ccst.2024.100306

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