Co-authored by ZGF Architects (ZGF), Fast+Epp, EllisDon, and Lafarge, “Concrete: A Pragmatic Approach to Lowering Embodied Carbon,” is a free and publicly available technical guide that outlines strategies to reduce concrete’s impact in construction, which can be implemented with no or negligible added project cost.
Construction Canada (CC) spoke to ZGF principal, Iain MacFadyen, to learn more about the guide.
CC: Why did the authors decide to release this guide?
ZGF: Concrete is both one of the most carbon intensive and most widely used materials in the built environment. Reducing its impact is critical to addressing the climate crisis. ZGF and our co-authors wanted to raise awareness about the strategies that project teams can take immediately to reduce this impact.
CC: What are some of the tips outlined in the guide?
ZGF: There are several strategies outlined in the guide, including:
- Collaboration. Effective collaboration among project teams from the start is critical to success, as is ensuring all key decision makers are involved.
- Start early. Setting carbon reduction goals early allows for the evaluation of a greater number of opportunities to reduce the embodied carbon of concrete—though it is not too late for projects already in design to optimize concrete mix design.
- Reduce concrete volumes. Utilizing less concrete volume per floor area, leading to lower overall embodied carbon, can be accomplished through designing a more efficient structural system.
- Optimize mix design. Concrete mix design optimization, including altering the amount of supplementary cementitious materials (SCMs), can minimize cement and significantly reduce the embodied carbon of a given concrete mix.
Many of these strategies, including concrete mix optimization, can be implemented with no or negligible added project cost.
CC: How is ZGF implementing low-carbon concrete on your projects?
For every project in ZGF’s Vancouver office, we utilize the guidelines, which are nimble and easily digestible, for a simple but effective approach to low carbon concrete. This includes a collaborative approach from the start of our projects, engaging in early conversations with the client, structural engineer, and construction teams to understand the baseline, target, and potential opportunities to reduce concrete’s impact.
One example is a 10-storey commercial tower in the city of Surrey, British Columbia, where we minimized the concrete volume through reduced floor-to-floor height and an optimized core layout. We also modified the concrete supplier bidding form to include performance requirements for all concrete elements, including a three-day stripping strength for concrete slabs.
The guide can be accessed here.
