Study Sees Potential for Storing Carbon in Common Building Materials
By Fay Harvey
DAVIS, Calif. — In a study published on Jan. 10, civil engineers and earth systems scientists at Stanford University and the University of California, Davis, found that construction materials such as concrete, asphalt, wood, brick and plastic have the potential to store billions of tons of climate-harming carbon dioxide.
Carbon storage, also known as carbon sequestration, occurs by taking carbon dioxide from its production point, converting it into a stable form and placing it where it has no ability to contribute to the atmosphere. Most recently, professionals have proposed injecting carbon underground or storing it deep in the ocean. However, these solutions pose financial, practical and environmental harm.
Though carbon sequestration through building materials alone cannot significantly reduce greenhouse gas emissions, using materials with carbon-storage capabilities in construction, alongside other protective climate efforts, could greatly decarbonize the environment. Researchers found that fully replacing conventional building materials with CO₂ -storing alternatives in new infrastructure could store as much 18.3 ± 3.1 billion US tons of CO₂ each year—roughly 50% of anthropogenic CO₂ emissions released in 2021.
Graduate student Elizabeth Van Roiijen led the study at UC Davis, where she researched how to leverage materials already ordered in mass quantities for carbon storage. Alongside Sabbie Miller, associate professor of civil and environmental engineering at UC Davis, and Steve Davis, a scientist at Stanford, Van Roijen investigated common building materials and their carbon-storing potential.
The researchers identified several opportunities for carbon reduction in common building materials, including incorporating biochar, a carbon-rich solid waste, into concrete; producing concrete and asphalt aggregates from carbon-infused artificial rocks; using biomass-derived plastics and asphalt binders instead of those made from fossil petroleum; and adding biomass fibers to bricks.
Out of all the materials studied, concrete was found to have the highest carbon-storing potential due to its yearly production rate of more than 22.05 billion tons a year. Miller believes even a little bit of carbon storage in concrete could go a long way, according to a UC Davis statement. Calculations from the study showed that if 10% of the world’s concrete aggregate production were “carbonateable,” it could absorb a gigaton of CO2. To achieve this, scientists would add carbon to aggregates, the granular material composed of crushed stone, sand, slag and other synthetic sources that is mixed with water to produce concrete.
“The feedstocks for these new processes for making building materials are mostly low-value waste materials such as biomass,” Van Roijen said in a UC Davis statement. “Implementing these new processes would enhance their value, creating economic development and promoting a circular economy.”
Many of the technologies found are ready to be adopted and put to the test. Others still need to be validated for their material performance and net-storage potential before being placed in real-world scenarios.
For the next steps, the researchers suggest enacting policy mechanisms to support these new carbon-storage initiatives and developing robust product standards and performance metrics when the materials go through more rigorous testing. In the meantime, researchers recommend prioritizing bio-based plastics, biomass bricks and wood as carbon-sequestering materials, particularly for non- or low-load-bearing applications such as insulation and flooring to minimize performance risks.