What’s holding up the greening of concrete?

Tuesday, 21 October 2025

Concrete is the second most widely used material in the world after water.

There’s no shortage of innovation and the development of alternative products in the drive to decarbonise concrete itself, or its use, but the process is not happening as fast as it should be, an international expert says.

Concrete needs to decarbonise because it is the second most widely used material in the world after water, and has a high carbon footprint. Its production accounts for about 8% of global carbon emissions.

But at the Concrete NZ conference in Auckland last week, keynote speaker Clare Tubolets, chief executive officer of SmartCrete CRC in Australia, said the industry needed to think about why it was not decarbonising more quickly.

Under the Paris Climate Agreement, Australia, like New Zealand, was working towards a target of economy wide net zero emissions by 2050. Within that goal, Australia was to achieve at least 60% reduction in embodied carbon by 2035.

“Embodied carbon” is the total greenhouse gas emissions associated with a building's or product's lifecycle, from raw material extraction and manufacturing to construction, use, and end-of-life disposal.

Tubolets said all of Australia’s major building companies have committed to the net zero carbon goal, and there was a roadmap for the cement and concrete sector to get to net zero.

Systemic barriers are holding back the decarbonisation of concrete, SmartCrete CRC’s Clare Tubolets says.

It meant there was a lot of activity and great innovation in that space, but it was not translating into everyday work, she said.

“I’ve had so many conversations with highly skilled engineers around Australia where I’ve asked them ‘if you were asked to remove 60% of the embodied carbon from the structure you are designing now, could you do it?’ The answer is ‘yes’ every time.

“But when asked ‘will you do it?’, the answer is ‘no’.”

To help the process, there were design innovations, such as novel reinforcement technologies; concrete innovations, such as the reduction of binder content; alternative supplementary cementitious - or “like cement” - materials, and new CO2 efficient materials.

“So why aren’t we decarbonising, and at a faster pace?”, Tubolets asked.

“What we keep hearing is that it’s due to cost, risk, policies, standards, a lack of incentives, no awareness or limited agility in the supply chain, that people don’t have the knowledge & skills they need, and/or there are no carbon data measurement systems available.”

But not a single one of those issues talked to the technical performance of any of the solutions that now exist; rather, those problems were all systemic issues, she said.

That had left SmartCrete CRC focusing on eight systemic barriers it had identified that needed to be addressed to accelerate adoption of the new technologies.

People don’t realise how central concrete is to their lives, Tubolets says.

Those barriers included complex supply chains that revolved around the time-cost-performance equation, over-prescriptive procurement policies, a knowledge asymmetry whereby information was not translated to clients and tradies, and the cost of innovation investment.

Tubolets said that for decarbonisation to truly be on the agenda it needed to be driven by government, and carrots (incentives) and sticks (penalties) had to be woven into legislation.

“We might all be passionate about our sustainability journey but unless there is a legislative requirement for us to follow, our markets won’t do this alone. We need to see better leadership from government, and policies to enable it.”

It was also necessary to create an environment where the supply chain felt comfortable adopting new products that had been tested and certified for use, she added.

“There is a temptation to, say, just replace concrete with the likes of engineered timber, but that’s not practical when New Zealand uses about 4 million cubic metres of concrete per year, while Australia uses about 30m cubic metres.

“People don’t realise how central concrete is to the built environment and infrastructure across the board. It is part of so much of the way we live, and it can be part of the solution to sustainability challenges too.”

Asked what industry could do in the drive towards decarbonisation, she said it could advocate for sustainable options, share and discuss barriers, price carbon into business decisions, and keep informed about innovations.

There is a risk of inertia if industry does not get clear direction, Global Cement and Concrete Association’s Andrew Minson says.

International concrete authority Dr Andrew Minson, from the Global Cement and Concrete Association, gave a keynote presentation on progress on the global decarbonisation roadmap and how the commitments made were translating into practical action.

There was a risk of inertia where governments did not think they could impose things on industry, while industry wanted clear direction, he told The Post.

“If industry is given that clear direction, they'll then act, but there’s a business reality, that they might not be able to deliver all that they potentially could if they had the right policies in place.”

There needed to be a positive feedback loop around what industry could do to equip government to act, and set a direction which would prompt further industry action, he said.

“It isn't just a single exchange, it's an iterative loop that needs to go round quite a few times. There'll be the early adopters and voluntary schemes and then we'll move to the mandatory schemes. And that is absolutely happening.”

While progress in the United States had slowed at a federal level under President Trump, many US states had doubled down on their efforts, and there was significant progress in the European Union, and other countries, including New Zealand, he said.

“Innovations and initiatives are being incorporated by industry, but when you bring in the carbon capture, utilisation and storage you can only go so far with the supplementary cementitious materials. You need to have it all.”

For example, scanning electron microscopy could help cut the ratio of “clinker” or the central binding ingredient in cement ratio, by 50%, and that would halve the amount of carbon capture and storage needed. That in turn halved the energy needed, and the overall cost premium on the industry.

Minson said it was also important for decarbonisation to be industry-led and guided, and commended Concrete NZ for developing a roadmap that was more integrated than anywhere else in the world.

“It puts them in a really strong position, and gives them a much better opportunity to actually deliver against the roadmap. The commitment they've got to decarbonise is exemplary.”