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By 2030, RBC has projected that Canada will need to build 5.8 million new houses, adding up to 18 million tonnes of greenhouse gas (GHG) emissions to the nation’s annual carbon footprint and require over $40B of capital investment each year. To meet this demand and reduce its impact on our climate, it is crucial to support new innovations in sustainable building technology.

When looking at a building’s environmental impact, emissions are often discussed in the context of embodied carbon, the emissions resulting from the production and use of the materials used in construction, and operational carbon, the emissions resulting from the building’s use throughout its lifetime. While retrofits can help to reduce operational carbon, embodied carbon is locked in during a building’s construction phase, must be addressed with smart design choices.

Isobloc, a Quebec company founded in 1985, has long been at the forefront of building material innovation. Its insulated masonry blocs have a unique design incorporating a polystyrene core encapsulated by architectural concrete layers. This improves the energy efficiency and environmental performance of new construction.

The design of Isobloc products impacts both the embodied and operational carbon of a building through reducing the overall amount of concrete used, along with its associated emissions, and improving a building’s capacity for temperature regulation with high thermal storage capacity and insulating properties.

In 2025, Isobloc teamed up with CarbiCrete, a leader in Canadian concrete decarbonization, to produce a line of products labeled Isobloc ZÉRO. CabiCrete’s technology produces concrete products without cement. Though cement makes up just 10-15% of a concrete mix, it is responsible for over 90% of concrete’s significant carbon footprint. CarbiCrete replaces 100% of cement with steel slag, a byproduct of the steelmaking industry, and cures its products using carbon dioxide, reducing emissions and trapping CO2 permanently within the concrete.

Through combining CarbiCrete’s EPD-verified reductions in embodied carbon with Isobloc’s innovative insulated masonry design, Isobloc ZÉRO is a clear choice for architects, designers, engineers, and contractors looking to build with higher performance and a lower carbon footprint. Isobloc ZÉRO is available now through Isobloc.

With 70 per cent of the global population projected to live in urban areas by 2050, resilient and sustainable construction is crucial to meeting our current and future infrastructure needs. While concrete has been proven to be one of the most resilient building materials available, its massive environmental impact must be addressed to justify its continued use.

One avenue for reducing concrete’s carbon footprint is through the integration of carbon mineralization curing into the concrete production process. CO₂ injection into wet concrete mix or by the curing of products in a dedicated carbon dioxide curing chamber locks emissions away into the concrete.

When CO₂ reacts with calcium oxides in concrete’s binding material, it transforms into calcium carbonate, which hardens the concrete and traps CO₂ within the molecular structure. The conversion of CO₂ to carbonate minerals is a safe and effectively permanent form of long-term CO₂ storage.

In a recent study published by researchers at the University of California, Santa Barbara, it was determined that building materials that utilize carbon mineralization technology in their production could annually store between 13.2 and 20 Gt of CO₂ by 2100.

This study also assessed carbon mineralized construction materials in comparison to their conventional counterparts. It found that “many of the carbon-storing building materials we considered have the potential to be cost competitive with the conventional materials they replace owing to the low cost of feedstocks needed.”

In a 2020 assessment of carbon mineralization and carbon capture, utilization, and storage (CCUS) technologies, researchers from the University of Greenwich in Chatham, UK found that mineralized construction products will be crucial to meeting low-carbon construction goals, and that wide product certification is a must for the rapid adoption of this technology into the construction industry.

The CarbiCrete process makes use of steel slag, a byproduct of the industrial steelmaking process, as a 100% replacement for cement, concrete’s conventional binding agent. The steel slag binder enables the permanent storage of CO₂ in a variety of concrete products.

Because the CarbiCrete process entirely replaces cement, the co-benefits of CarbiCrete’s technology extend beyond carbon sequestration to waste valorization, emissions avoidance, and contribution to the circular economy. Through combining cement replacement with carbon mineralization curing, CarbiCrete is developing a revolutionary construction technology with far-reaching positive implications.

Cement-based concrete is the most-used manmade material on the planet, but it is responsible for 8% of annual greenhouse gas (GHG) emissions each year. Over 90% of these emissions are due to the use of cement, a key binding agent in concrete. Innovative technologies that replace cement are crucial for reducing the impact of our built environment.

One approach to reducing concrete’s emissions is the partial replacement of cement with supplementary cementitious materials (SCMs). Mixing alternative binders with cement can partially reduce concrete’s carbon footprint. Slag cement is one such SCM that allows concrete producers to replace some cement content in the concrete mix with blast furnace (BF) slag.

CarbiCrete’s technology replaces 100% of cement in the concrete mix with steel slag, a byproduct of the basic oxygen furnace (BOF) or electric arc furnace (EAF) steelmaking process. Combined with carbonation curing, CarbiCrete technology can reduce concrete’s carbon footprint by over 20 times compared to a conventional cement-based process.

With so many similarities in the language we use to discuss slag cement and CarbiCrete’s steel slag binder, here’s four major differences that set CarbiCrete apart:

1. Absolutely no cement

Slag cement requires the use of ordinary Portland cement (OPC) to create a suitable binder in the concrete mix— according to the Slag Cement Association, slag cement can replace no more than 50% of cement in the concrete mix, or 80% in specific applications. CarbiCrete’s steel slag binder enables 100% cement replacement. Without cement, the global warming potential of end products made with CarbiCrete technology is significantly reduced.

2. Carbon mineralization curing

Concrete products manufactured using slag cement are cured with water and conventional curing methods. CarbiCrete’s steel slag binder reacts with CO₂ gas in our patented curing chambers instead of water. Through carbon mineralization, the CO₂ and slag react to form the calcium carbonate that gives concrete its strength.

Carbon mineralization not only reduces the products’ curing time from 28 days to 24 hours, it also permanently sequesters CO₂ emissions within the concrete products. This means that even after the concrete has been destroyed, emissions stay permanently trapped within the chemical structure of CarbiCrete products.

3. Available supply and green steel compatibility

Slag cement makes use of ground granulated blast furnace slag (GGBFS), which is produced during the reduction of iron ore to iron in a blast furnace. Blast furnaces are extremely carbon-intensive, often relying on fossil fuel and a decreasing supply of virgin material. Hatch posits that by 2040, low-emission technologies like electric arc furnaces will encompass a significant portion of steel production.

The steel slag utilized in the CarbiCrete process is a waste material generated when iron is processed into steel. It has limited uses and often ends up in a landfill. The EAF steelmaking process is considered the frontier of green steelmaking technology; it utilizes scrap metal that is expected to maintain a steady supply in coming years.

4. Cost

Due to a decreasing supply and a significant demand for GGBFS, the North American market is increasingly served through overseas imports. As a consequence, slag cement is not only more emissions-intensive than the CarbiCrete process, it’s also more costly. Additionally, cement prices are expected to steadily increase in coming years due to increased demand for new buildings, and a rise in raw material prices, making steel slag an attractive replacement: less expensive and easier to acquire, steady supply and ability to replace 100% of cement in masonry and hardscape application.

CarbiCrete’s unique steel slag binder shows crucial improvements in cost, environmental performance, and long-term feasibility when compared to slag cement. As the construction industry moves toward decarbonization, the elimination of cement and the incorporation of permanent CO₂ storage via mineralization are major benefits to CarbiCrete’s technology that make it an excellent long-term solution for the transformation of the sector.

As the built environment continues to grow and change with our societal needs, the environmental impact of construction projects must be considered to ensure sustainable infrastructure growth. One way to demonstrate a building project’s environmental impact is through certifications, the foremost of which is Leadership in Energy and Environmental Design (LEED) certification.

In order to achieve LEED certification, a construction project must abide by certain criteria meant to standardize the quantification and reduction of a project’s overall environmental impact. The LEED system, as regulated by the United States Green Building Council (USGBC) and Canada Green Building Council (CAGBC), has evolved through several versions since its inception in the 1990s.

LEED v5, the newest version of LEED’s guidelines, went through two rounds of public comment in 2024 and is expected to open for registration in early 2025. When developing LEED v5, three central impact areas were prioritized: decarbonization, quality of life, and ecological conservation and restoration. As a result, the forthcoming LEED v5 guidelines are some of the most far-reaching yet, promising to deliver on sustainability and innovation.

The priority areas of LEED v5 are echoed in updated prerequisites and credits. One notable area of improvement when comparing LEED v5 to its predecessor is the inclusion of embodied carbon as a major sustainability quantifier. Material selection is now codified in a new Materials and Resources prerequisite, as well as an embodied carbon-focused credit.

The “Assess and Quantify Embodied Carbon” prerequisite has been developed as part of LEED v5 to encourage the assessment and quantification of the materials used in the project. The goal of this assessment is to encourage the knowledge and reduction of embodied carbon, the carbon dioxide emissions that result from the manufacturing and processing of building materials.

The “Reduce Embodied Carbon” credit is a new addition to the credit to the LEED v5 credit library. With up to six points available, embodied carbon is given significant weight in the new LEED system. This credit utilizes global warming potential (GWP) as quantified in environmental product declarations (EPDs) to quantify the environmental impact of the materials used in a new construction project.

CarbiCrete’s innovative technology enables the production of concrete products without using cement. The products utilize an industrial byproduct, steel slag, as a binding agent and are cured via carbon mineralization, leading to the permanent sequestration of CO₂ within the end-product. This combination of emissions avoidance and carbon dioxide removal, when quantified in an EPD, reduces the GWP of a concrete masonry units (CMU) by over 90%, to just 11.7 kg CO₂e per m³ of concrete. Compared to CarbiCrete’s impact toward achieving LEED v4.1 certification, CarbiCrete can make an even greater impact under the LEED v5 framework.

One of the requirements that must be complied with to receive points under the new “Reduce Embodied Carbon” credit is the identification and reduction of the top sources of embodied carbon predicted in the project. With cement-based concrete often serving as a major emissions source in new construction projects, incorporating new technologies like CarbiCrete’s is one way to achieve the six possible points in this credit and work toward LEED certification of a project under the updated requirements of the v5 framework.

Environmental Product Declarations (EPDs) are quickly becoming an essential part of the building design and construction processes. In 2024, CarbiCrete and Climate Earth, a leader in construction industry EPDs, developed a site-specific EPD for CarbiCrete’s pilot commercial production of cement-free concrete products at Patio Drummond.

Chris Erickson, the CEO of EPD leader Climate Earth, discussed the history of EPDs in Concrete Products magazine. Erickson notes that, in addition to US federal promoting the use of low-embodied carbon concrete verified via EPD, “many cities and 35 states are now, or are in the process of, developing low carbon standards for concrete. The implications of these changes are clear. Low carbon, measured by EPDs, has become a hard purchase metric and a business imperative for any concrete producer that wishes to participate in major projects around the country. “

EPDs are crucial for both manufacturers and product users, like architects, engineers, and designers, to demonstrate the sustainability of a building project through its choice of products. For a project to obtain LEED certification or other signifiers of improved environmental performance, specifying products with available EPDs can demonstrate a verified sustainability impact. Under LEED v4.1, using products with verified EPDs can help a building project receive up to 2 LEED points.

The Canadian low-carbon assets through life cycle assessment (LCA²) initiative, led by the National Research Council, convened from 2019-2023 to develop outputs to encourage low-carbon procurement, including a centralized repository for Canadian life cycle inventory (LCI) datasets of primary construction materials. The initiative also published national guidelines for whole-building life cycle assessments to assist project owners in implementation of carbon reduction strategies.

The LCA­­­² initiative’s primer for federal government procurement notes that embodied carbon can contribute up to 50% of a building’s total long-term emissions, and that “at 12 years embodied carbon is ~75%, and concrete ~40%, of the total emissions.”

The primer recommends various strategies to reduce a project’s embodied carbon, particularly through optimizing the cement content in the concrete used: “the amount of embodied carbon in concrete is primarily a function of how much cement is used in the mix.” By reducing cement use in the concrete mix, a project has the opportunity to greatly reduced its embodied carbon emissions.

In future years, EPDs will see increased adoption and regulation via legislative requirements. Although projects seeking LEED certification are likely to specify products with available EPDs, this is not yet a stipulated priority for more general projects. In the United States, EPDs are required for material suppliers in states including New York, New Jersey, and California, with more states moving toward requiring verifiable reductions in embodied carbon.

When it comes to concrete, precast concrete and masonry products show a vast improvement over ready-mix concrete in terms of environmental performance. This is clear when looking at precast and ready-mix concrete’s cradle-to-gate industry-wide EPDs: per cubic metre, Canadian precast concrete has a weighted average total global warming potential (GWP) of 205.38 kg CO₂e, while Canadian ready-mix concrete has an industry average benchmark of 304.52 kg CO₂e.

Climate Earth, a leader in on-demand EPDs that produces 95% of all concrete-related EPDs in North America, has developed an EPD that measures the environmental impact of CarbiCrete’s cement-free concrete masonry units (CMUs). The cradle-to-gate facility-specific EPD was produced using data gathered onsite at Patio Drummond, a leading concrete manufacturer and CarbiCrete’s initial commercial production partner. The EPD measures the environmental impact for CarbiCrete cement-free CMUs at 11.7 kg CO₂e per cubic metre.

When compared to the Canadian Concrete Masonry Producers’ Association industry-wide EPD for CMUs manufactured in Eastern Canada, CarbiCrete represents an extraordinary improvement upon masonry’s already impressive environmental impact. The CarbiCrete process allows for a complete replacement of cement with an industrial byproduct, reducing embodied carbon while contributing to the principles of the circular economy.