Unlike other materials, concrete is inherently local, and products vary widely by geography. Supplementary cementitious materials are often used to reduce the GWP of concrete, but availability of these is also dependent on location. The CRMCA recently published an industry average EPD for concrete produced in BC [4]. This allows designers to establish the realms of possibility for different mix requirements.

In addition to specifying “low-carbon” concrete, designers can minimize their carbon footprint by:

• Minimizing the volume of concrete, they use on a project. Use concrete only where necessary, and do not use concrete where the strength or durability properties of concrete are not required. Maximize the structural capacity of the concrete, avoid over designing elements.
• Minimizing the volume of the project itself. For example, question whether the additional garage is really needed or if the basement is necessary to achieve the project needs.
• Consider setting total GWP goals for the project, and allowing the concrete mix designer to have flexibility in how they achieve this goal. Specifying minimum SCM contents can place conflicting requirements on concrete suppliers, which may lead to an increase in GWP, or alter other aspects of performance. Additionally, overuse of SCMs in buildings can cause shortages of SCMs in other industries (infrastructure for example). Dams, bridges, and other large infrastructure projects often rely on SCMs to limit early thermal cracking. If SCMs are not available to those projects, additional reinforcement may be required to control cracks instead. It is important to have an understanding of availability of resources, after all the end goal is to mitigate climate change globally, and not minimize embodied carbon on one project to the detriment of many others.

For different regions in BC, the following concrete suppliers provide the lowest GWP concrete.