What you need to know:
- While the aviation industry has worked towards reducing its carbon footprint, the construction industry’s environmental impact has remained relatively overlooked.
- In what could be a game changer in the construction industry, the at Washington State University (WSU) researchers incorporated environmentally sustainable biochar.
Researchers have developed a formula that significantly reduces carbon emissions from conventional concrete without altering its mechanical properties.
After water, concrete is the other most widely utilised material in the construction industry. It’s estimated that four billion tonnes of concrete are manufactured each year. But it comes at a cost. Making ordinary cement requires high temperatures, combustion of fuels. Limestone, which is used as an ingredient, produces carbon dioxide as it decomposes. This results in almost eight per cent of global carbon emissions.
This is 5.5 per cent more than what the aviation sector produces. While the aviation industry has worked towards reducing its carbon footprint, the construction industry’s environmental impact has remained relatively overlooked.
In what could be a game changer in the construction industry, the at Washington State University (WSU) researchers incorporated environmentally sustainable biochar and charcoal derived from organic waste and strengthened beforehand, with concrete wastewater. The biochar was able to absorb up to 23 perc ent of its weight in carbon dioxide from the air.
After treating the biochar in the concrete washout wastewater, they were able to add up to 30 per cent biochar to the cement mixture. The resulting paste, made from this biochar-amended cement, exhibited an impressive compressive strength after 28 days, reaching levels comparable to that of ordinary cement at approximately 4,000 pounds per square inch. Once constructed, this biochar-enhanced concrete continues to absorb and trap carbon dioxide for the entire duration of its existence, which can range from 30 years on the pavement to 75 years on a bridge.
“With this, we should be able to help get to carbon neutrality of the built environment. The trick is really in the interfacial engineering—how you engineer the interfaces in the concrete,” said Xianming Shi, a WSU civil and environmental engineering professor.
The team is now working to patent their invention, scale up production of their new concrete and licence their technology for commercialized development.