Week 23 Concrete

Upcycling CO2 and waste into greener concrete

Concrete bricks - Photo credit, Pexels & Free Images - Pixabay

Welcome to the twenty third edition of my weekly blog where I take a closer look at the policies adopted by individual countries in their efforts to meet the requirements of the Paris Agreement. Particular attention is paid to the role that Carbon Capture, Utilisation, and Storage (CCUS) research and technologies are playing in the drive to meet these requirements.

Introduction
This week I take a look at how advances in carbon capture and utilization technologies are being exploited to convert carbon into concrete. I will also feature companies such as Carbon Cure, Carbon Upcycling UCLA and Carbicrete, all NRG COSIA Xprize semi-finalists, and how they are utilizing captured carbon in the concrete industry.

Converting Carbon into Concrete
The process of converting carbon into concrete is known as concrete curing. CO2 flue gas that will otherwise go to waste and pollute the environment is instead used to cure precast concrete. The CO2 is permanently stored within the concrete as unreactive limestone, increasing the quality of the concrete and making it more durable.
Precast concrete is where concrete is molded into shape off-site, transported to the construction site and slotted into place. A good example of precast concrete is staircases built for suburban housing units.

Carbon Cure
Carbon Cure is headquartered in Dartmouth, Nova Scotia, Canada. The problem their technology is solving is how to reduce the carbon footprint of concrete produced.

Their technology is retrofitted into the existing processes in place at the concrete plants. CO2 captured from large industrial emitters such as oil refineries is purified and liquified before being transported to the concrete plant. The CO2 is then injected into the wet concrete during the mixing stage of the production process. The CO2 is permanently converted into a solid mineral. The concrete produced is of a higher quality and greener for the environment and thus helps solve the problem of reducing the carbon footprint of the concrete industry.

Carbon Upcycling UCLA
Carbon Upcycling ULCA (CUU) is a collaborative CCUS initiative involving scientists, engineers, and economists at the famous Californian University.

Upcycling is the process of transforming byproducts or material waste into new materials. CUU use flue gas extracted from smoke stacks and converts it into ‘CO2NCRETE’. CUU also use 3D printing technology to shape their precast concrete in whatever shape is required.

Next steps for CUU is to develop the technology further at a lab scale and increase the volume of the material produced.

Carbicrete
Carbicrete is located in Montreal, Canada. Carbicrete is a cement-free, carbon-negative concrete solution. Typically, concrete is made with portland cement and the significance of this is that cement based concrete production accounts for roughly 5% of global CO2 emissions.

With Carbicrete’s technology, the concrete is made with steel slag, a glass like byproduct in steel production that is usually sent to landfill. Like, Carbon Cure, the CO2 is injected into the wet concrete during a process called carbon activation. Because cement is not used in the production of the concrete and CO2 is sequestered in the concrete, the final product is carbon-negative.
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Summary
The concrete industry is an established and important one in any functioning economy around the world. That is why it is so important from an environmental perspective that exciting companies such as Carbon Cure, Carbon Upcycling UCLA and Carbicrete answer the call to find ways of reducing the carbon footprint of the concrete industry. We look forward to finding out how these companies and others continue to innovate and help solve the growing CO2 emissions challenge.
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Next week’s blog will profile Slovenia and their efforts to meet their CO2 emissions reduction targets.