As the global economy shifts toward decarbonisation and electrification, much of the focus – rightfully – has been on reducing emissions from energy production, transportation and manufacturing.
The International Energy Agency expects demand for fossil fuels to peak before 2030 at our current rates of electrification, as clean energy alternatives are rapidly brought online to replace them.
With clean energy and storage technologies advancing at pace, attention has turned to another major carbon emitter – concrete.
“Aside from water, there’s no material on Earth we use more than concrete,” Bill Gates tweeted last year.
“That’s why it’s so important to figure out how to decarbonise it.”
Single largest industrial polluter globally
The vast majority of modern concrete production uses a 200-year-old chemistry – Portland Cement.
Made from mixing limestone, clay and silica at high temperatures, Portland Cement is essentially the binder that holds concrete together, giving it strength and longevity.
It’s also one of the worst industrial sources of carbon emissions in the world.
“If cement manufacturers were a country, they’d be behind only China and the US in terms of global emissions,” Suvo Strategic Minerals Ltd (ASX:SUV) executive chair Aaron Banks explained.
“The industry produced 8% of global emissions, the equivalent of the global car fleet, and that’s just not acceptable.”
SUV is developing two new types of more environmentally friendly cement – Climate Tech and Hybrid cement.
In its Climate Tech product, the company is replacing Portland Cement with a geopolymer substitute made from industrial by-products like nickel slag and fly ash, repurposing waste materials into a low-carbon cement alternative.
While Climate Tech Cement hasn’t been tested as extensively as the old faithful Portland, SUV estimates – based on recent lab tests – that it would be suitable for 80% of precast concrete applications.
“Using a geopolymer cement made from nickel slag, fly ash and rice husks, we can reduce the carbon footprint of the cement by about 90% compared to Portland,” Banks highlighted.
“That would be the equivalent to taking 900 million cars off the road.”
So why not replace Portland Cement entirely?
Much like with switching from combustion engines to electric, battery-driven vehicles, the process is more complicated than simply switching out option A for option B.
Concrete quite literally forms the bedrock of modern society. We make roads, bridges, homes and even entirely new land masses out of the stuff.
Above all else, a structural product like concrete must be predictable. That requires intensive testing, both across environmental settings and over long periods.
Making such a fundamental switch to how we produce materials also carries a cost penalty – over 4 billion tonnes of Portland Cement is produced each year in purpose-built kilns that would need to be refurbished or abandoned altogether.
The road to completely replacing Portland Cement is likely to be a long one for that reason but the wheels have already begun to turn.
“Concrete is the world’s most used building material and provides the foundation for renewable energy transition, resilient infrastructure and new homes around the world,” Global Cement and Concrete Association chief executive Thomas Guillot said.
“Global cooperation on decarbonising concrete is a necessity as countries developing their infrastructure and housing will be the biggest users of concrete in the coming decades.
“I envision a world in the not-too-distant future where the foundation of a sustainable, zero-carbon global economy will literally be built with green concrete.
“We now need governments around the world to work with us and use their huge procurement power to advocate for low-carbon concrete in their infrastructure and housing needs,” Guillot added.
“We require their support to change regulation that limits the use of recycled materials and impedes the transition to a low carbon and circular economy.”
A mid-term compromise
While the path to a net-zero cement industry will not be a quick or easy one, steps are already being taken within the industry to reduce carbon emissions wherever possible.
Suvo’s Hybrid Cement is a compromise in that spirit, offering a “bridge” between Portland Cement and sustainable alternatives that reduced the use of traditional materials by up to 70%.
“We don’t make houses the same way we did 200 years ago and we certainly don’t make cars the same way. There’s a reason for that,” Banks laughed.
“It’s likely that Portland Cement has a time horizon. Eventually tariffs will be placed on it.
“Companies and governments are pushing for ambitious targets. They can no longer just discard industrial by-products in irresponsible ways.
“They’re looking for better solutions, to be able to do the right thing.”
As industry and government continue to transform supply chains, manufacturing processes and industrial standards, replacing Portland Cement with a low-carbon alternative seems inevitable.
The question now, much like in the electric vehicle and battery sector, will be exactly which emerging technology rises up to take its place.