Construction materials like concrete and plastic have the ability to sequester billions of tons of carbon dioxide, as highlighted by a recent study conducted by civil engineers and earth systems scientists from the University of California, Davis and Stanford University. This research, published on January 10 in Science, indicates that when combined with efforts to reduce carbon emissions in the economy, storing CO2 in buildings could assist in achieving global greenhouse gas reduction targets.
According to a recent study by civil engineers and earth systems scientists at the University of California, Davis and Stanford University, construction materials such as concrete and plastic may have the capacity to sequester billions of tons of carbon dioxide. The findings, published on January 10 in Science, suggest that when paired with efforts to decarbonize the economy, CO2 storage in buildings could significantly contribute to the global aim of lowering greenhouse gas emissions.
“The potential is quite substantial,” remarked Elisabeth Van Roijen, who spearheaded the study while a graduate student at UC Davis.
The objective of carbon sequestration is to capture carbon dioxide from the source of its emission or directly from the atmosphere, convert it into a stable state, and sequester it in a way that it no longer contributes to climate change. Various methods have been proposed, such as injecting carbon underground or storing it in the ocean, but these methods come with practical difficulties and environmental concerns.
“What if, instead, we could utilize materials that we already produce in abundance to store carbon?” Van Roijen posed.
Collaborating with Sabbie Miller, an associate professor of civil and environmental engineering at UC Davis, and Steve Davis from Stanford University, Van Roijen assessed the potential for carbon storage within a variety of common building materials, including concrete (which consists of cement and aggregates), asphalt, plastics, wood, and brick.
Globally, over 30 billion tons of traditional forms of these materials are produced annually.
Concrete potential
The investigated carbon-storing methods encompassed the incorporation of biochar (derived from heating waste biomass) into concrete, leveraging artificial rocks loaded with carbon as aggregates in concrete and asphalt, developing biomass-based plastics and asphalt binders instead of fossil fuels, and integrating biomass fibers into bricks. These technologies range in development status, with some still in lab or pilot stages and others ready for implementation.
Researchers discovered that while bio-based plastics could sequester the most carbon by weight, the most significant potential for carbon storage lies in utilizing carbonated aggregates in concrete. This is largely due to concrete being the most widely used building material globally, with over 20 billion tons produced each year.
“If feasible, even a small amount of carbon storage in concrete could have a substantial impact,” Miller stated. The team estimated that if 10% of the worldwide concrete aggregate production were convertible to carbonate, it could capture one gigaton of CO2.
The raw materials for these new methods of producing building materials primarily consist of low-value waste products like biomass, as noted by Van Roijen. Implementing these new techniques would not only increase their value but also foster economic growth and encourage a circular economy.
Some advancements in technology are required, particularly to confirm the material performance and net storage potential of the various manufacturing methods. However, many of these technologies are on the verge of being adopted, Miller commented.
Van Roijen is currently a researcher at the U.S. Department of Energy National Renewable Energy Laboratory. The research was funded by Miller’s CAREER grant from the National Science Foundation.
