Innovations in Carbon Capture for Construction

Created By RISC | 2 months ago

Last modified date : 2 months ago

CCUS (Carbon Capture, Utilization, and Storage) is a comprehensive approach to reducing carbon dioxide emissions from factories or direct air. Once captured, the CO₂ can be used in various applications, such as enhanced oil recovery or the production of chemicals and materials, providing economic value while reducing emissions. Alternatively, the captured CO₂ is securely stored underground in geological formations, ensuring that it remains sequestered and does not contribute to climate change.

During all these major efforts, construction is playing its part and taking on new ideas. The industry is starting to use new carbon capture tech to cut emissions and even turn them negative. By adding carbon capture to building materials, construction can switch from releasing greenhouse gases to removing them. This article will look at some key materials and methods to make carbon capture work in construction, showing how the industry can significantly help tackle climate change.

Carbon-Cured Concrete
One promising approach is carbon-cured or carbonated concrete, where waste CO₂ is injected into the fresh concrete mix. The carbon dioxide reacts with cement to form calcium carbonate nanomaterials that get permanently embedded in the concrete matrix, trapping the CO₂.[1] This process can sequester 5-20% of the concrete's weight as CO₂ while also increasing compressive strength.[2] Systems have been developed to capture CO₂ directly from industrial sources like power plants or cement kilns and transport it to concrete batch plants for utilization.[3][4] The resulting carbon-cured concrete is stronger and has a lower carbon footprint.

Carbon Mineralization Products
Other researchers are exploring ways to mineralize captured CO₂ into solid carbonates that can be used as construction materials themselves. At UCLA, CO₂ was mineralized with industrial brine wastes into calcium and magnesium carbonates that could replace some cement or aggregate components.[5] These mineralized CO₂ products could potentially be used in concrete or as construction binders or aggregates.

Integrated Carbon Capture Systems
An MIT team designed an electrochemical system that captures CO₂ from a cement plant's emissions and converts it into synthetic limestone (CaCO₃) pellets that are then incorporated back into the concrete production process on-site.[6]

Biomass and Biochar
Plant biomass can also help capture and store carbon in construction through approaches like biochar. Biochar is a carbon-rich solid produced by heating biomass such as wood waste in a low-oxygen environment. Studies found adding biochar to concrete could increase strength while permanently sequestering the biomass carbon.[7]

Timber Construction
Using timber and mass timber products is one of the most straightforward ways constructions can become carbon-negative. As trees grow, they absorb CO₂ from the air through photosynthesis, storing it in their woody biomass. Using this timber in buildings keeps the sequestered carbon locked up for decades. Lifecycle assessments show wood buildings can have substantially lower embodied carbon than steel or concrete structures.[8] New mass timber techniques allow larger timber buildings up to 18 stories tall.[9]

Overcoming Challenges
Overcoming challenges in implementing carbon capture in construction is paramount given the sector’s substantial carbon footprint and the high costs and energy intensity involved. The key hurdles for validating permanent CO₂ sequestration include ensuring occupant comfort and safety. While material-based CCUS technologies such as timber construction and biochar composites offer immediate opportunities, their CO₂ absorption capacity is limited. Chemical-based solutions such as CO₂-cured concrete show promise but require thorough evaluation of environmental tradeoffs. Collaborative efforts are crucial to facilitate CCUS implementation aligned with sustainable development goals in cities, including advancing research, providing incentives, securing financing, fostering public engagement, and integrating systems planning. Ultimately, overcoming challenges will pave the way for carbon capture technologies to play a vital role in urban decarbonization and the transition to net negative emission assets.

Story by Difei Miao RISC Advisor, CCUS Research Project Consultant, Nanotech Specialist

References:
1. Ravikumar, D., Zhang, D., Keoleian, G. et al. Carbon dioxide utilization in concrete curing or mixing might not produce a net climate benefit. Nat Commun 12, 855 (2021). (https://doi.org/10.1038/s41467-021-21148-w)
2. Reuters. "Concrete traps CO2 from soaked air in climate-friendly test." Reuters, February 3, 2023. (https://www.reuters.com/business/sustainable-business/concrete-traps-co2-soaked-air-climate-friendly-test-2023-02-03/)
3. American Chemical Society. "New Way to Capture and Recycle Carbon Dioxide from Industrial Emissions." ACS PressPac, August 2023. (https://www.acs.org/pressroom/presspacs/2023/august/new-way-to-capture-and-recycle-carbon-dioxide-from-industrial-emissions.html)
4. Kulasuriya, C.; Vimonsatit, V.; Dias, W.P.S. Performance based energy, ecological and financial costs of a sustainable alternative cement. Journal of Cleaner Production 2021, Volume 287.
5. La Plante, E.C.; et al. ACS Sustainable Chemistry & Engineering 2021, 9 (32), 10727-10739.
6. MIT News (2022). Cracking the carbon removal challenge. (https://news.mit.edu/2022/cracking-carbon-removal-challenge-verdox-0915)
7. Mensah, R.A.; et al. Biochar-Added Cementitious Materials—A Review on Mechanical, Thermal, and Environmental Properties. Sustainability 2021, 13, 9336. (https://doi.org/10.3390/su13169336)
8. Andersen, C.E.; et al. Embodied GHG Emissions of Wooden Buildings—Challenges of Biogenic Carbon Accounting in Current LCA Methods. Frontiers in Built Environment 2021, 7.
9. Autodesk. "Mass Timber Construction." https://www.autodesk.com/design-make/articles/mass-timber-construction