Concrete is the most widely used construction material on the planet. Globally, we produce over fourteen billion cubic metres of it every year — enough to build a footpath from the Earth to the Moon and back more than a dozen times. That scale comes with a significant environmental footprint. Cement production alone accounts for roughly eight percent of global carbon dioxide emissions, and the extraction of sand and gravel for aggregate places pressure on natural resources and ecosystems.
But the industry is not standing still. Across Australia and around the world, concrete manufacturers, researchers and builders are developing and adopting practices that reduce the environmental impact of concrete without compromising the structural performance that makes it indispensable. Here is a look at the key areas where change is happening.
Supplementary Cementitious Materials
One of the most effective ways to reduce the carbon intensity of concrete is to replace a portion of the Portland cement in the mix with supplementary cementitious materials. These include fly ash, a byproduct of coal-fired power generation; ground granulated blast-furnace slag, a byproduct of steel manufacturing; and silica fume from silicon production. Each of these materials reacts chemically with water and calcium hydroxide in the concrete to form additional binding compounds, contributing to strength while reducing the proportion of high-emission clinker required.
Blended cements containing thirty to sixty percent supplementary materials are now commonplace in Australian concrete production. They often deliver equal or superior long-term strength and durability compared to straight Portland cement mixes, particularly in marine and sulfate-rich environments. The reduction in embodied carbon can be substantial — a forty percent slag blend, for example, can cut the carbon footprint of the cement component by roughly the same proportion.
Recycled Aggregates
Aggregates — the sand, gravel and crushed rock that make up sixty to seventy-five percent of concrete by volume — are traditionally sourced from quarries. This extraction process consumes energy, generates dust and noise, and permanently alters landscapes. Recycled concrete aggregate, produced by crushing demolished concrete structures, offers a viable alternative for many applications.
Recycled aggregate can replace a significant portion of natural aggregate in lower-strength and non-structural applications such as footpaths, kerbing, pipe bedding and subbase layers. In some jurisdictions, recycled aggregate is also permitted in structural concrete when processed to meet Australian Standards for grading, density and contaminant limits. As demolition volumes increase and landfill levies rise, the economic case for recycled aggregate continues to strengthen.
Water Management
Concrete production requires water for mixing, curing and equipment cleaning. Forward-thinking producers are implementing closed-loop water systems at batching plants, capturing and recycling washout water rather than discharging it. Reclaimed water can be used in subsequent batches, reducing both water consumption and the volume of slurry waste that needs disposal.
At the project level, pervious or permeable concrete — a specialised mix with an open aggregate structure — allows rainwater to drain through the slab and into the ground below. This reduces stormwater runoff, recharges groundwater tables and can eliminate the need for conventional stormwater infrastructure on smaller sites. Permeable concrete is increasingly specified for car parks, pedestrian areas and residential driveways in water-sensitive urban design zones.
Carbon Capture and Low-Carbon Cements
Several emerging technologies aim to fundamentally change the emissions profile of cement production. Carbon capture and storage involves capturing carbon dioxide from kiln exhaust gases and either storing it underground or using it in other industrial processes. Some producers are experimenting with injecting captured carbon dioxide directly into the concrete during mixing, where it reacts with calcium compounds to form stable mineral carbonates, effectively locking the carbon into the finished product.
New cement chemistries are also under development. Geopolymer cements, made from industrial byproducts activated by alkaline solutions rather than fired clinker, can achieve comparable strength to Portland cement with dramatically lower emissions. While still in the early stages of mainstream adoption, geopolymer concrete is being used in selected infrastructure projects across Australia and is expected to become more widely available as standards and supply chains mature.
Local Sourcing and Shorter Supply Chains
Transport emissions are often overlooked in concrete's environmental footprint, but they add up quickly. Trucking aggregates and cement long distances increases fuel consumption and road wear. Producers like Clustries reduce this impact by sourcing aggregates from nearby quarries and operating a network of batching plants close to the communities they serve. Our South Australian plants in Welland, Dry Creek, Lonsdale, Gawler and other regional centres minimise haulage distances for the majority of our customers.
Shorter supply chains also mean fresher concrete. Because ready-mix concrete begins setting from the moment it is batched, shorter delivery distances allow for more precise scheduling and less material waste due to loads that arrive outside their workable window.
Environmental Product Declarations
Transparency is a growing expectation in the construction industry. Environmental Product Declarations provide independently verified data on the environmental impact of a product across its full lifecycle — from raw material extraction through manufacturing, transport, use and end-of-life disposal. An increasing number of concrete producers, including major Australian suppliers, now publish EPDs for their product ranges.
For specifiers, architects and builders pursuing Green Star, NABERS or other sustainability ratings, EPDs provide the data needed to quantify and compare the environmental performance of different concrete products. Choosing a supplier that publishes EPDs demonstrates a commitment to accountability and helps the broader industry move toward lower-impact practices.
What You Can Do
If sustainability matters to your project, start by asking your concrete supplier about their environmental commitments. Specify blended cements where appropriate, consider recycled aggregate for non-structural applications, and choose a local supplier to minimise transport emissions. Every project is an opportunity to make a better choice.
To discuss sustainable concrete options for your next project, contact the Clustries team. We are happy to share information about our materials, processes and environmental performance.