Using more Sustainable Concrete in Construction

When it comes to emissions, low carbon concrete is becomming commonplace in the New Zealand market. Understanding the key construction and design differences will assist the wider adoption of this in your project.

Concrete is everywhere—in our roads, buildings, and infrastructure. But the traditional concrete we've relied on has a significant carbon footprint. Thankfully, innovations are emerging that offer lower emissions alternatives that help us align with maturing stakeholder requirements.

One key challenge is that traditional concrete production is highly energy-intensive, releasing large volumes of CO2. However, forward-thinking suppliers and engineers across the country are stepping up with solutions that greatly reduce environmental impact without compromising strength or performance.

Low-carbon concrete differs from traditional concrete in its composition, often using supplementary cementitious materials (SCMs) like fly ash or slag, and alternative binders such as geopolymer mixes. These materials introduce specific challenges, including longer curing times, variability in setting characteristics, and differences in workability. For instance, geopolymer mixes might require longer curing periods before achieving full strength, affecting project timelines. The consistency of mixes with high levels of fly ash can also vary significantly, potentially complicating quality control efforts. Additionally, finishes on low-carbon concrete may initially differ in appearance, requiring adjustments in finishing techniques to achieve desired aesthetics. However, these challenges are manageable through proactive strategies, including comprehensive testing of mix designs, clear communication and close coordination with suppliers, and targeted training for contractors and construction crews. By proactively addressing these considerations, teams can smoothly integrate low-carbon concrete into their projects without sacrificing quality or efficiency.

The New Zealand construction market is evolving, with clients increasingly prioritising sustainability and low-emissions options. Given that concrete is often a significant factor in an overall emissions budget for a project, it makes sense to focus on this first. Suppliers nationwide are providing a range of lower emissions concrete. As designers, contractors, and clients, it's essential we stay informed about these innovations and support their integration into projects.

And it's great to see it happening right if front of us - a great example being East Coast Concrete, managed by Derek Watson, recently established and supplying low emissions concrete to Tairawhiti. Great work!