Sustainable Solutions for the Future of Concrete
Together, building and construction are responsible for 39% of all carbon emissions (WGBC, 2019). For this reason, concrete (the most widely used construction material in the world) is under increasing scrutiny. But how do you change an industry of this magnitude? We highlight some innovations striving for transformation.
- To make Portland cement – the most common, standard variety of cement, and a key component in concrete – pulverised limestone is heated to high temperatures using coal. Both the burning of coal, and gases released by the limestone release huge amounts of CO2.
Researchers at MIT have developed a production method that could eliminate these emissions. Their technology uses an electrochemical process to dissolve the limestone, and therefore substitute the use of fossil fuels with clean, renewable electricity. Although the process produces high-purity CO2, this can be easily sequestered and harnessed to produce value-added products, such as dry ice, meaning no emissions are released into the atmosphere.
- Scientists at UCLA have come up with a technology that turns industrial CO2 emissions into concrete products, using the process of CO2 mineralisation. Gaseous CO2 is converted into solid mineral carbonates, which can then be mixed into cement.
- US company Heliogen has developed a way to harness the extremely high temperatures required to produce cement – using solar energy. Precisely aligned mirrors centre sunlight onto a single target to create the energy. The process could be used in place of burning fossil fuels.
- Researchers at the University of Colorado have developed a type of ‘living’ concrete using cyanobacteria, which could be used as a lower-carbon alternative to traditional concretes.
The bacteria is grown in a scaffold of sand and hydrogel, which supplies moisture and nutrients to ensure proliferation and mineralisation – a process similar to the formation of seashells. The living nature of the material means it has self-healing and CO2-absorbing properties.