Concrete and cement manufacture is a highly environmentally damaging process, responsible for nearly a tenth of total global carbon emissions. It is resource intensive, using vast amounts of energy, virgin materials such as sand and lime, and water. Clearly, a more sustainable alternative is needed.
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Several new building materials have been developed in recent years to improve the carbon footprint of the construction industry and urban areas, with varying degrees of success. Whilst there are some notable developments in this area, the fact remains that concrete is cheap, easy to produce, and possesses suitable physiochemical properties.
CarbiCrete is a Montreal-based company that is seeking to change the face of construction by developing sustainable materials that adequately replicate concrete’s properties whilst significantly reducing the industry’s greenhouse gas emissions.
What is CarbiCrete’s Solution?
CarbiCrete has come up with an innovative solution to the environmental impact of concrete manufacture by producing a cement-free alternative. The material utilizes steel slag, an industrial byproduct, as a binder. Up to 150 kg of carbon dioxide is removed per ton of concrete produced.
Aside from reducing emissions by replacing the heavily carbon-intensive cement, this approach also solves another critical environmental problem indicative of the construction industry: the over-use of virgin, non-renewable resources.
By using an industrial byproduct, the process fits with the aims of the circular economy, a hot-button topic in the environmental sector currently. This concept focuses on the utilization of waste streams that would have previously been sent to landfills or disposed of into the environment and lost.
CarbiCrete’s process is similar to conventional concrete production, which should make it easy to adopt by the construction industry. However, there are a number of key differences between it and traditional processes.
The main difference, as mentioned above, is the use of steel slag rather than conventional carbon-intensive cement. This material is then mixed with materials such as blast furnace slag (a lightweight green aggregate) and water using standard equipment to produce the concrete.
Specialized equipment is used to produce CarbiCrete’s low-carbon material, namely an absorption chamber. In this chamber, carbon dioxide is injected, which cures the concrete. This process takes 24 hours to produce concrete with sufficient strength that can then be used in buildings.
In this process, CO2 is captured permanently and converted into calcium carbonates, which give the material its strength by filling the voids within its matrix. This could have further benefits for tackling climate change by sequestering atmospheric carbon dioxide and converting it into a usable product.
According to CarbiCrete’s website, this sustainable steel slag-based concrete possesses comparable or even superior physical, mechanical, and durability properties.
The water absorption properties of CabriCrete’s concrete are comparable to conventional alternatives, but the material has higher compressive strength. Furthermore, the process produces a product with better resistance to freezing and thawing, a key durability issue in current structures.
Analyzing the Material’s Net Carbon Negative Lifetime Impact
To confirm the material’s net carbon-negative benefits, lifecycle assessments were conducted by the company. Even considering additional factors like transportation and conversion, the company has found that this innovative solution results in a net carbon-negative material that can be used in a wide range of commercial products.
By completely eliminating the use of carbon-intensive Portland cement and sequestering CO2, which is then mineralized during curing, the company has stated that the product reduces carbon emissions by 100% during manufacture. An economic analysis was also performed.
About the Company
An American Concrete Institute, National Slag Association, and Concrete Masonry & Hardscapes Association member, CarbiCrete is headquartered in Lachine, Quebec, Canada. Co-founded by Chris Stern and Mehrdad Mahoutian, the company aims to provide the construction industry with sustainable solutions to the climate crisis.
CarbiCrete has been recognized as one of the fastest-growing sustainable companies in Canada for the past two years by Corporate Knights as part of its Future 50 ranking, which highlights 25 public and 25 private sector companies driving the world toward a green future.
The global construction industry urgently needs innovative green solutions if it is to meet its net-zero targets. New materials, processes, and new working practices and governmental policies will make up the bulk of any environmental strategy over the coming decades.
CarbiCrete has developed a revolutionary alternative to conventional concrete which, if employed at scale, could help to drive a rapidly urbanizing globe toward a more sustainable outlook.
By replacing traditional virgin materials with industrial waste byproducts and sequestering carbon dioxide in the process, CarbiCrete’s concrete has a vastly lower carbon footprint than conventional alternatives. Solutions like this could help humanity avoid the worst predicted effects of anthropogenic climate change.
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References and Further Reading
Carbicrete (Homepage) Available at: