Across the building sector, changes in how work is done, materials used and the process on and off site are changing faster than ever.
Within this, moves toward more sustainable practices and materials are gathering pace for several reasons, including cost, efficiency, legislative requirements—and because it’s the right thing to do for our planet.
The reduction in embodied carbon is a huge part of creating buildings that have less negative impact on our world, and the move towards this is being strongly driven by consumer desire.
Concrete represents the largest proportion of embodied carbon in the vast majority of construction, so offering products with a reduced embodied carbon content was important for Boral, one of Australia’s largest building supplies companies.
Boral’s head of product solutions Nathan Barrell said the creation of lower-carbon concrete products had been driven from inside and outside Boral.
“Our customers need to lower the embodied carbon in their projects for a range of reasons, including legislation, end-user pressure and because it’s the right thing to do,” he said.
“This is true across the range of our customers, from huge construction firms who have carbon emission reduction targets to meet, to home renovators and the like who just want to use a more sustainable product.
“As well, Boral as a company is committed to reducing our carbon footprint and our shareholders have that expectation too.”
Performance was key to the range, Barrell said.
“The majority of the embodied carbon content in concrete is within the Portland cement element,” he said.
“This can be reduced through replacing it with other materials such as fly ash or blast furnace slag, and there’s nothing new in that.
“However, this can impact some aspects of the concrete’s performance such as increasing the time it takes for the concrete to go off.
“That is not an issue in some applications, but for others, such as structural elements or flooring in buildings, it is, as it slows down the whole construction process, which increases costs. It can also have higher drying shrinkage rates than ‘traditional’ concrete.
“These issue were solved with our ENVISIA product, which has up to 60 per cent less Portland cement, and offers similar early age strengths to ‘traditional’, has up to 50 per cent less shrinkage than traditional products and greater flexural strength.
“It is a high-performance, lower carbon concrete and as such has a higher price point than lower performing products.
“This means it doesn’t suit every need—apart from budget restraints, it can also be more in terms of performance and quality than is needed for the job, such as a footpath.”
Barrell said that at the other end of Boral’s Lower Carbon Concrete Range, Envirocrete offered lower embodied carbon and was suitable for a range of application where early age strength was not an issue, as well as being competitively priced versus lower strength ‘traditional’ concrete.
Creating a product that would fit between the two became a focus for Boral’s in-house research and development team here in Australia.
After intensive research, development, testing and creativity, the team developed Envirocrete Plus.
This new offering, which was launched earlier this year, has achieved the ‘dream’—a lower carbon concrete with similar performance to ‘traditional’ concrete and a price point to match.
This product has 40 to 60 per cent less Portland cement, achieves good early-age strength and is suitable for most post tensioned applications. It also achieves up to 25 percent less shrinkage compared to conventional sustainable concrete mixes.
“We are now able to offer customers a full range of products that tick all the boxes: performance, sustainability and value,” Barrell said.
“With Envirocrete Plus, clients who needed higher performance than Envirocrete but didn’t have the budget or need for Envsia can still reduce their embodied carbon content—we’ve met them in the middle.
“It also means our suite of lower carbon products can suit any kind of project and need, literally from skyscrapers to a pad for a backyard shed.
“Whatever the project, embodied carbon can be significantly reduced, and we think that’s a win across the board for everyone.
“Lower carbon concrete is the new normal. It is what the industry and indeed consumers want and need.
“Other manufacturers offer low carbon products, but none can currently match our ability to provide the right type of product for the job—they don’t have the range.
“There’s now no trade-off in using lower carbon concrete.”
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