Let's put emissions to work in concrete jungles

The future of Canada's cities lies not just in the skylines they shape but in the very materials from which they are built. In our quest for sustainable development, one sector presents both a formidable challenge and a promising opportunity: the cement and concrete industry.

Cement production alone is responsible for about seven per cent of global carbon-dioxide emissions, equivalent to a quarter of all industrial emissions. In Canada, with our commitment to achieve net-zero emissions by 2050, transforming this “hard to abate” sector is not just beneficial — it's imperative.

With a substantial carbon footprint, this sector is ripe for transformation through carbon capture and utilization (CCU) technologies that result in alternative materials, presenting a critical solution for Canada's green growth and prosperity.

First, a chemistry lesson. The terms “cement” and “concrete” are often used interchangeably, but they actually refer to different materials. Think of it as if we were baking a cake: in this analogy, concrete would be the cake itself and cement would be the flour. Cement acts like glue when mixed with water, binding together the various ingredients — such as sand and gravel

— to form concrete, the solid material we see in everything from sidewalks to skyscrapers.

The route to decarbonization in the cement sector isn't simple as the primary challenge lies in its chemistry. Even if we electrified every cement kiln worldwide and use renewable energy, twothirds of the emissions would persist due to CO2 being released from heating limestone to high temperatures.

Research by Mckinsey & Co. indicates that the cement sector is among the most emission-intensive, generating the highest CO2 emissions per dollar of revenue. This correlation suggests that without substantial interventions, any increase in cement demand could lead to proportional increases in CO2 emissions. This is particularly concerning as projections estimate the global built environment will double by 2060 — effectively building the equivalent of one New York City every month for 40 years.

Alternatives to cement, known as supplementary cementitious materials (SCMS), are used to decarbonize this space, but conventional SCMS are in short supply in many regions, putting immense pressure on the SCM sector to innovate and expand its capabilities.

There is a massive opportunity to leverage this materials gap for transformative change.

CCU is up to the task of bridging at least a portion of that gap. By capturing emissions from industrial processes and directly incorporating them into building materials, CO2 can be converted into a solid form and used in concrete.

For example, at Carbon Upcycling, we specialize in creating alternative SCMS by carbonating or mineralizing low-grade or waste solid feedstocks, which would not typically be considered for use in the cement sector. When mixed into concrete, this transformed CO2 not only enhances the material properties but also turns a typical building material into a durable medium that stores carbon.

By activating these materials, we offer a sustainable substitute for a portion of cement in various concrete applications such as readymix, precast or bagged products.

The good news is that many CCU technologies are complementary, not mutually exclusive of other technologies. For instance, our technology could be paired with systems that use recycled concrete or demolition waste as aggregate, reintegrating these materials into new constructions. This technology prevents waste and reduces the demand for new, virgin materials.

Likewise, in specialized areas such as the precast concrete sector, some innovative companies have successfully eliminated the use of cement altogether, showcasing substantial strides toward reducing the industry's carbon footprint.

The transition to a climate-centric built environment demands a reimagined circular economy — one where materials are not only recycled and reused but also actively contribute to carbon reduction.

Canada can become a leader in tech-enabled natural resource management by using solid and emission wastes through innovative CCU and circular economy models. This approach propels us toward a more resource-efficient future.

The next time you stroll through your city, take a moment to observe the concrete that surrounds you. As we envision the next generation of urban landscapes, let us recognize and reimagine the role of the built environment as a transformative medium for CCU and the circular economy.

This redefinition turns our cities into active participants in our quest for a greener, more prosperous future.