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Balancing carbon reduction with long-term durability, construction is turning to advanced concrete admixtures to build safer, stronger and more sustainable infrastructure.

The industry is increasingly looking toward admixtures as a means to meet sustainability targets and goals. Image courtesy of Chryso North America.

Sustainability has become the construction industry’s defining challenge. From embodied carbon accounting to net-zero targets, contractors, designers and material suppliers are all grappling with ways to lower emissions while keeping projects on budget and on schedule. Concrete, as the world’s most widely used building material, sits at the centre of this conversation.

Cement, concrete’s binding ingredient, is responsible for roughly seven per cent of global CO2 emissions. For many stakeholders, it’s “the elephant in the room.” But the path forward is not about eliminating concrete, it’s about producing, specifying and using it smarter. That’s where admixtures deliver new solutions, helping to reduce cement content, improve performance and integrate new supplementary cementitious materials (SCM).

Yet, there’s a missing dimension in today’s sustainability dialogue: resilience. It’s not enough to focus only on reducing environmental harm. We must also ensure our structures can withstand hazards of fire, flood, wind and seismic events. In short, true sustainability requires resilience.

Admixture solutions cannot simply be environmentally sustainable, they must also be resilient enough to withstand natural hazards ans seismic events. Image courtesy of Chryso North America.

Resilience: the missing half of sustainability

In 2015, three landmark frameworks emerged from the United Nations: The Sustainable Development Goals, the Paris Agreement and the Sendai Framework for Disaster Risk Reduction. While the first two frameworks have managed to capture widespread attention, the Sendai Framework, despite its direct relevance to our built environment, remains underutilized in mainstream construction dialogue.

Why does resilience matter? Because a “green” building that fails during the impacts of a wildfire or hurricane is not sustainable at all.

Rebuilding doubles the carbon footprint, displaces communities and disrupts economies. Data from Saint-Gobain’s Sustainable Construction Barometer underscores the shift: resilience is gaining traction globally, particularly in regions exposed to natural hazards. The percentage of respondents prioritizing resilience to climatic events jumped to 21 per cent, the largest increase recorded to date.

Concrete plays a central role here. Its inherent fire resistance, structural integrity under seismic stress and durability in water and wind-prone regions make it indispensable for resilient construction. From seismic-resistant foundations in Mexico City to hurricane-rated walls in Florida, concrete continues to prove itself as one of the most hazard-resilient materials available.

The Canadian Climate Institute reports that every dollar spent today on climate adaptation can return $13 to $15 in direct and indirect benefits over time. For the construction industry, investing in resilient infrastructure isn’t just smart planning – it’s a long-term gain for both communities and the economy.

Chryso Convert C, transforms returned plastic concrete into a dry, hardened, granular state, making it easy to handle and reuse. Image courtesy of Chryso North America.

A lever for carbon reduction

In practice, a sustainable concrete mix should look and perform just like a conventional one. The difference lies in how it is optimized behind the scenes. The goal is to minimize the carbon footprint by reducing cement, maximizing SCMs and using local resources. Admixtures are the enablers of this shift, unlocking multiple pathways to cut carbon without compromising performance.

Four strategies illustrate how:

1. Cement reduction through strength enhancers

Admixtures like strength enhancers enable producers to achieve equal or greater performance with less cement. High-range water reducers and like EnviroMix SE deliver early and late strength gains of 2.4–4.0 MPa, allowing up to 10 per cent cement reduction without compromising quality.

2. Maximizing SCM use

Supplementary cementitious materials, including metakaolin and waste-stream products, are increasingly used. Admixtures offset challenges like slower strength gain or higher water demand, enabling greater cement replacement while maintaining performance.

3. Optimizing local materials

Declining access to high-quality sand drives the use of manufactured and marginal local sands. Admixtures, such as the ChrysoQuad line, improve workability, reduce variability and lower transport emissions.

4. Enabling circular economy practices

Products like ChrysoConvert C recycle returned concrete into usable aggregates. Together, these strategies lower carbon while maintaining performance.

Admixtures present a lever for contractors to achieve carbon reductions. Image courtesy of Chryso North America.

Performance under extreme conditions

In Canada, sustainability solutions cannot be divorced from performance. Alberta illustrates this reality vividly. With temperatures swinging from -30°C in the winter to +30°C in the summer, producers face unique challenges: hot, dry and windy conditions in summer lead to plastic shrinkage cracking and rapid slump loss, while extreme cold creates curing difficulties.

Effective curing has long been a challenge in this region, and concrete mixes must be designed to maintain durability across these extremes.

Canadian standards provide clear guidance on these challenges. The National Building Code of Canada (NBCC) requires that concrete structures are designed for expected temperature ranges, wind loads and snow/water loads over their intended service life. Additionally, CSA A23.1 cold weather and hot weather concreting guidelines set limits on concrete placement, curing methods and admixture use to maintain performance in extreme climates.

Admixtures are essential to meeting these demands. They extend slump life, improve finishability and support mixes that achieve reliable strength gain even under punishing conditions. In addition to workability control, durability remains a central requirement in the Canadian climate. Air-entraining agents play a critical role by creating an engineered air-void system with proper spacing factor and distribution. This controlled microstructure allows internal pressure relief during freeze–thaw cycles and improves resistance to salt scaling – a major durability concern in regions where de-icing salts are widely used. Crucially, sustainable concrete must look and act like conventional concrete. Contractors should not have to compromise workability or strength in exchange for carbon savings. By tailoring mixes with advanced admixtures, we can ensure that sustainability and performance are aligned, even in one of the world’s most demanding climates.

Admixtures must perform in extreme Canadian conditions. Image courtesy of Chryso North America.

Resilience tools: building resilience index

Material science, however, is only half the picture. Measuring resilience in a systematic way is equally important if we are to balance carbon reduction with long-term durability. This is where tools like the Building Resilience Index (BRI), developed by the International Finance Corporation, come in.

Unlike green certifications that focus mainly on mitigation, BRI evaluates a building’s ability to withstand four major hazards: wind, water, fire and geoseismic activity. A sustainable concrete mix must never mean weaker concrete. With advanced admixtures – strength enhancers, water reducers and SCM-enabling technologies – we can lower carbon while ensuring structures perform under extreme conditions.

While BRI provides a useful global framework, the concept of resilience takes on a unique urgency in Canada. The country already faces some of the most aggressive climate stressors in the developed world: record wildfire seasons in British Columbia and Alberta, catastrophic flooding in Quebec and New Brunswick, coastal erosion in Atlantic Canada and accelerated freeze-thaw deterioration in the Prairie provinces due to increasing temperature variability. These events have triggered a national shift from reactive repair to proactive resilience engineering, not only for buildings, but also for highways, water systems, transit networks and energy infrastructure.

Unlike many countries that rely solely on voluntary sustainability programs, Canada is formalizing resilience in codes, policy and public procurement. The Climate Resilient Buildings and Core Public Infrastructure (CRBCPI) initiative, led by the National Research Council of Canada (NRC), has introduced engineering guidance that goes beyond historical weather data by using future climate models that project performance over a 50 to 75-year service life. The goal is to design for evolving climate loads, more severe freeze–thaw cycles, higher rainfall intensity, wildfire heat exposure and longer durability expectations, all of which have direct implications for concrete specification and mix design.

As a practical outcome, resilience is now embedded in Canadian construction standards. The CSA S6:25 Canadian Highway Bridge Design Code requires climate resilience assessments and hydrological risk modeling. CSA A23.1/A23.2 concrete standards emphasize exposure class–based durability, stable air-void structure and resistance to chloride penetration and sulphate attack, critical for marine, transportation and northern construction environments. Provinces like Ontario and British Columbia now include resilience criteria in public infrastructure tenders, meaning ready-mix producers and specifiers must demonstrate durability performance, not just compressive strength.

Canada also recognizes that resilience is not only a materials issue – it’s a societal and economic priority. Through the federal Disaster Mitigation and Adaptation Fund (DMAF), resilience metrics are now tied to eligibility for major infrastructure funding. In Northern Canada and Indigenous communities, climate resilience strategies prioritize reliable performance in extreme environments where permafrost movement, remoteness and short construction windows present unique engineering challenges. In these regions, the durability of concrete relies heavily on technology-enabled mix designs, including low-temperature accelerators, shrinkage-reducing admixtures and engineered air-entrainment systems that improve resistance to freeze-thaw damage and surface scaling.

Image courtesy of Chryso North America.

A holistic view: sustainability + resilience

The conversation should not pit carbon reduction against resilience. In fact, they reinforce each other. Durable structures mean fewer rebuilds, avoiding the “hidden carbon” of reconstruction. Concrete, properly designed with admixtures, can meet both mandates: lowering embodied carbon while delivering superior resilience.

The construction sector is entering a new era. Net-zero goals remain urgent, but they must be paired with resilience benchmarks to ensure buildings can withstand tomorrow’s hazards. Tools like BRI, combined with admixture-driven low-carbon solutions, offer a way forward.

For the Canadian construction industry, success will depend on collaboration between engineers, producers and policymakers. And with the right technologies and mindset, we can build a future that is not only lower carbon but also stronger, safer and more resilient.

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