Chief Executive's Upfront
Supporting Engineers to Deliver Quality, Low-Carbon Projects

Concrete NZ was pleased to exhibit at the recent SESOC Conference in Wellington - an important opportunity to connect with structural engineers, share industry developments, and reinforce our ongoing commitment to collaboration across the built environment.

Rob Gaimster, Chief Executive

Our presence focused on two key messages. First, the importance of specifying concrete supplied from a plant independently audited under the Concrete NZ Plant Audit Scheme. Second, the growing need to prioritise “low-carbon” concrete solutions - and how these can be reliably specified and sourced.

Structural engineers play a vital role in influencing material decisions. By specifying concrete from a Plant Audit Scheme-certified supplier, engineers can have confidence the product meets rigorous quality standards. Each participating plant is audited by experienced professionals and must demonstrate conformance with NZS 3104 through regular testing and reporting. The Scheme ensures consistent, compliant concrete and significantly reduces the need for project-specific site testing - saving time, cost, and administrative burden.

In short, the Plant Audit Scheme is a convenient, comprehensive, and cost-effective quality assurance tool for engineers and specifiers.

At the same time, the sector is progressing rapidly in its decarbonisation efforts - and engineers are key enablers of that progress. One practical step is to specify “low-carbon” concrete. This term refers to concrete mixes with a Global Warming Potential (GWP) lower than the average conventional mix of the same strength class, based on tools like the NZ Green Building Council's Embodied Emissions Methodology.

Understanding the GWP of available concrete mixes can be supported by reviewing third-party verified Environmental Product Declarations (EPDs). Concrete NZ members have invested significantly in EPDs, which provide a robust foundation for assessing and comparing the carbon impact of different mixes. While limitations exist, EPDs offer engineers a transparent method for embedding emissions considerations into project specifications.

When specifying low-carbon concrete, it is essential to set performance-oriented requirements based on a targeted GWP reduction relative to a recognised New Zealand baseline. This approach gives ready mixed concrete suppliers the flexibility to achieve outcomes using the most appropriate means - such as incorporating locally available Supplementary Cementitious Materials (SCMs).

This method also accounts for all emissions associated with concrete production up to the point it leaves the batching plant. It recognises the carbon intensity of specific cement sources and accommodates geographical realities - such as aggregate availability - which can influence cement demand and, consequently, carbon footprint.

Finally, we encourage structural engineers to engage with their local ready mixed concrete supplier early in the design process. Understanding material availability and logistical capacity from the outset ensures that specifications are both ambitious and achievable - and ultimately, that the project delivers on its sustainability and performance goals.

Concrete NZ remains committed to supporting engineers with the tools, guidance, and confidence to design and specify smarter, lower-carbon concrete.