architecture business

Interview: How CEMEX are pioneering low carbon concrete

In discussions around sustainability, two industries are often singled out as particularly difficult to decarbonise: aviation and cement. Both are relatively small in percentage terms, but will loom larger as carbon budgets shrink. Last week I was at the Futurebuild exhibition, where the building materials corporation CEMEX were launching Britain’s first low carbon concrete. I took the opportunity to speak to Andy Spencer, VP for Corporate Affairs and Sustainability for CEMEX Europe.

What are CEMEX presenting here today?

We’re launching a range of products under the brand name Vertua. They’re all presenting a low carbon version of the concrete purchased by the construction industry. The concept is to try and encourage discussion around carbon, talk about it with our customers and try to move people’s buying habits towards lower carbon solutions.

Cement is often described as difficult to decarbonise. Why is that?

People have a very significant perception around cement, and cement is a component of concrete – cement on its own doesn’t go into construction. The carbon footprint of cement as a standalone product, in its traditional form, is quite high: somewhere around 500 or 600 kg per tonne. When you put it into concrete the material footprint is obviously lower. In the UK the average tonne of concrete is under 100kg of embodied CO2.

And the problem with the cement itself is the chemistry of the process, right? You could run a cement factory on 100% renewable energy and still have a problem.

At the moment that challenge remains to be resolved. Our business in the UK is running on 100% renewable energy, and we’re running at over 60% non-fossil fuels to run the kilns. The trick around the chemistry of the process is partly what we’re launching with this product here. It’s using other materials to replace the clinker part of the cement within concrete. If you can replace that with other materials that are lower carbon, we bring the carbon footprint of the entire product down.

And what sort of carbon savings have you achieved with this new product?

The range has several sub-brands within it. If we start off with our Vertua Classic range, that reduction, compared to a traditional concrete, is somewhere between 30 and 50%. We then go through a range with higher levels of product substitution, right through to a very new novel cement which has been developed in our Swiss laboratory which represents a 70% reduction against traditional concrete.

Is there a significant price difference for low carbon concrete?

The pricing is not hugely different to other concretes in the Classic range. As we move on within the range there’s a series of options. As you can imagine, small scale innovation does command a premium, so what we’re hoping to do with this range is to come up with an economy of scale so that over time we can bring that price down. And of course as the price of carbon rises all these things will begin to level out. Above everything what we’re trying to do is to start a change. Pricing and application and technology are all something that people can come and talk to us about, because it will vary across different contexts.

The construction industry isn’t exactly know for embracing change. Are you seeing much demand for these sorts of products?

Had we been sat here a year ago, we’d be saying ‘yes there’s some interest, but no real drive for change.’ I think we’ve seen an incredible social movement in the last year. People’s awareness of the challenge, the climate emergency, and what we have to do as a society to tackle it, whilst still be able to get on with our daily lives, is really driving change at a fast pace. And it’s something that we really welcome, because we can be part of the solution.

How do we encourage low carbon concrete in the places where the most construction is happening, such as China?

Europe and the UK have to lead the way. Globally the cement industry is somewhere between 6 and 8% of emissions. Within Europe it’s less than 1.5%. What we need to do is drive the innovation, develop it here, in an area where we’ve got a good regulatory environment and where we’ve got carbon pricing to help support the technology development. Then as global businesses it’s our responsibility to push that and roll it out into our other operations as quickly as possible.

Where do you see the future of low carbon concrete? Could we ever get to a zero carbon concrete?

One of the products we’re launching here is a net zero carbon concrete. We are currently using an offset just for the last remaining section. We very carefully considered the type of offset that we’re using. We absolutely acknowledge that this is a temporary measure until we can bridge the gap. I’ve got every confidence that our industry will be there by 2050 at the latest. I think things are moving very fast. Technology is developing at a real pace, and we want to be part of the low carbon generation – the solution, not seen as an industry that’s traditional and not willing to change, because that perception is wrong.

So that’s what CEMEX are doing. What about the industry? Do you see wider change happening?

At the industry level I see a huge amount of discussion and change technically around how we become a sustainable industry. There is a recognition that we have a significant challenge, a recognition that people perceive us part of the problem. There is also a lack of knowledge of what we really are doing behind the scenes, and lack of knowledge around the true impact of concrete versus other materials in the built environment. But we are moving ahead as fast as we can. And we’ll try and develop the communications to ensure that people make the right choices, understand the full impact, and the end result is something that is durable, and is low carbon both in the build phase and the in-use phase.

  • You can find out more about CEMEX’s Vertua range here, and more about their climate plan.
  • I also spoke to the natural building guys and companies using alternatives to concrete. Those have their place too, but getting solutions to global scale is something only multinationals can do.
  • Chris Goodall’s book What we need to do now has a good discussion of concrete.

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