The Targets
Concrete NZ’s 2024 sustainability report outlines the industry’s commitments: a 44 percent reduction in direct and electricity-related CO2 emissions by 2030 against a 2020 baseline, and a net-zero carbon goal by 2050. These are significant targets for a material whose production process — the calcination of limestone to produce cement clinker — is inherently carbon-intensive. Approximately 60 percent of cement manufacturing emissions come from the chemical process of calcination rather than the energy used to fuel it, meaning that low-carbon energy alone is insufficient to decarbonise the sector.
The report draws data from producers representing approximately 80 percent of New Zealand’s ready-mixed concrete volumes, giving it broad industry coverage and making the progress data representative of sector performance rather than the most progressive individual firms.
Supplementary Cementitious Materials
The most significant measurable progress in the report is the growth in supplementary cementitious materials (SCMs) — blast-furnace slag, fly ash, and other industrial by-products that can replace a proportion of Portland cement in concrete mixes without compromising structural performance. SCMs now represent 6.6 percent of binders in ready-mixed concrete — more than four times their 2020 level. That growth rate is substantial and reflects both increasing availability of SCM supply and growing specifier willingness to accept lower-clinker mixes.
The practical implication for engineers and builders is that lower-carbon concrete mixes are increasingly available and have been demonstrated to meet structural and durability requirements in a widening range of applications. Specifying concrete without asking about SCM content is equivalent to not asking about embodied carbon at all — it is no longer a reasonable omission in a market where the information is available and the alternatives are proven.
Innovation in Practice
The report highlights several company-specific innovations contributing to sector-wide decarbonisation. Kayasand’s Engineered Sand technology produces manufactured sand from quarry fines, reducing demand for river-extracted sand. Eco-Cem products provide lower-clinker options for applications traditionally dominated by general-purpose cement. Digital delivery optimisation — using software to reduce truck wait times, improve load efficiency, and minimise returns with partially set concrete — reduces both emissions and operational cost.
What’s Coming in 2026
Concrete NZ is launching a “Transformation to a Low-Carbon Concrete Industry” project in early 2026, intended to accelerate the sector’s decarbonisation beyond the incremental progress achieved through SCM adoption and operational efficiency. Details of the project’s scope have not yet been released, but the scale of ambition — transformational rather than incremental — signals that the industry expects a significant structural change in how concrete is produced and specified in New Zealand over the next five to ten years. Builders and specifiers should engage with Concrete NZ’s communications on this project as it develops.
