Could disruptive technologies dramatically reduce the carbon footprint of concrete? New methods of making concrete show that it’s possible. Here are three innovations that could drastically cut the carbon footprint of construction.
Concrete is the most manufactured material in the world – it is also a major contributor to global carbon emissions. The high carbon footprint of concrete is mainly due to the production of cement – its key ingredient. Cement production alone contributes about 8 percent of global CO2 emissions. So much so, that if the cement-sector were a country, it would be the world’s third largest carbon-emitter, after the US and China.
There are already a number of methods to reduce the carbon footprint of concrete. This includes, for example, replacing a share of the clinker in cement with other materials such as fly ash, shifting away from the use of fossil fuels to produce cement and making cement more energy efficiently. At the same time, new ways of making concrete are showing that innovations in how concrete is made could also dramatically help cut carbon emissions. So, is concrete due for a makeover? Here, are three new technologies that could help disrupt the industry.
Researchers are showing that it’s possible to replace cement and make concrete using much less energy by using bacteria. In one process developed by the US start-up BioMason, sand is placed in molds and injected with microorganisms, which starts a process similar to the one that creates coral. The process happens at room temperature over a few days, without the need for fossil fuels or calcination – two of the main sources of the cement industry’s CO2 emissions. Among current applications, the material is being piloted by the U.S. air force to build runways.
In another adaption a team of researchers at University of Boulder Colorado have produced a concrete-like material by growing cyanobacteria in a mixture of sand and gelatin. The cyanobacteria (a class of microbes that captures carbon-dioxide) mineralize the gelatin and binds together the sand to form a hard “living” building material. Stored at room temperature in dry air, the blocks harden over a few days. Even after a few weeks, the bacteria in the blocks are still alive and a piece from an old brick can be placed with a new batch of raw materials to begin the process again.
The company Solidia, which has attracted investment from major energy firms including BP and Total, uses a process that replaces limestone in cement with a synthetic material. The process requires lower temperatures and less energy than traditional methods, and as the cement hardens, it absorbs CO2.
Concrete made with the company’s patented cement results in a production process that reduces carbon emissions by 70 percent, and it locks up about 300 kg of CO2 per ton as it cures. If such concrete-making technology succeeds in gaining traction, it could be a way of binding up large quantities of carbon dioxide into roads and other structures. As a first step in commercialization, Solidia is already using the technology to produce products such as pavers for patios and driveways. It is also collaborating with major concrete manufacturers, including LafargeHolcim, to test broader commercial use.
3D printing is not only used to print items such as auto-parts, it can now also be used to print concrete buildings. In one research effort, a team of researchers at UCLA have received a grant to make 3D-printed concrete that incorporates carbon dioxide, as part of the binder, which could cut the carbon footprint of this concrete by 60%.
Companies and researchers experimenting with 3D printing are also finding that it’s possible to dramatically cut down on the amount of concrete used during construction of a building through precision printing.