The Low Carbon Concrete Routemap, published April 2022, discusses the latest technologies and techniques to decarbonise concrete.
What is the Low Carbon Concrete Group?
The Green Construction Board’s Low Carbon Concrete Group, formed by industry professionals on a voluntary basis, has been meeting regularly since early 2020 to discuss the issues surrounding the decarbonisation of concrete.
Also discussed are the latest techniques and technology that can speed up the move to a zero-carbon future.
The result of these meetings is the Low Carbon Concrete (LCC) Routemap that was launched in April 2022.
What is the Low Carbon Concrete Routemap?
This free-to-download document is published by the ICE and endorsed by the Construction Leadership Council, the Concrete Centre and the Institution of Structural Engineers.
It provides objective advice on low carbon concrete, the actions that are necessary to get to a net zero future, and potential scenarios when they are implemented.
What makes the LCC Routemap different?
There are several route maps, or roadmaps, from the concrete industry, as well as broader documents that discuss the decarbonisation of concrete.
The LCC Routemap differs in these following important ways:
1. There’s no agenda to promote the use of concrete or a particular technology.
The document has been prepared on a voluntary basis by a broad cross-section of the industry, with representation from clients, designers, contractors, academics, concrete producers, and concrete technologists.
A core tenet of the document is that we use concrete more efficiently, i.e. achieving the same benefits with less.
2. The document emphasises the steps that can be taken now to make immediate savings.
These need not involve a reduction in performance or an increase in cost.
They’re simply the result of a conscientious focus on reducing carbon.
3. Finally, the routemap scenarios don’t rely on carbon capture use or storage to provide the savings.
However, it’s recognised that carbon capture can play a significant role overall as long as the technology can be developed, funded and rolled out at a sufficiently large scale.
How the LCC Routemap can help
The document seeks to address the full supply chain of concrete from design and specification to batching, mixing and the use of different cements.
There are therefore many areas which will be of use to different parts of the industry.
If we consider just one part though, the embodied carbon rating certificate, how would this be used?
Many clients and engineers have been looking for a benchmarking approach that would allow them to drive demand of lower carbon concrete by understanding what good looks like.
The carbon rating certificate provides just that.
Providing a benchmark
While concretes with the lowest carbon ratings aren’t suitable for all uses, the benchmark provides a solid starting point from which to assess how our concretes measure up against industry usage.
It can also help identify opportunities for improvement.
As such, it’s expected that clients and specifiers may seek to mandate at least the reporting of concrete carbon intensity against the benchmark if not going further by mandating a specific intensity threshold.
For example, ‘all concrete shall, on average, be less than a B rating according to the LCCG benchmark’.
The act of focussing attention on the carbon intensity of concrete will in turn lead to better data, lower carbon concretes and a strong incentive for innovation in the sector.
All of which are long overdue.
Keeping options open
It’s recognised that a focus on carbon intensity of concrete alone could lead to a dash to GGBS (Ground Granulated Blast-furnace Slag) blends, something already experienced in the industry.
While the optimised use of GGBS is part of the puzzle, it’s important to drive other alternatives which may be at an earlier stage in their adoption.
Some suppliers may seek to meet the demand for low carbon concrete solely through the use of GGBS, but this will rapidly become unsustainable given the overall supply limitations.
A September 2023 report from the Institution of Structural Engineers reviewed GGBS' global availability, and found that "any local increase in the amount of clinker substituted with GGBS is unlikely to decrease global emissions".
Encouraging competition for the benefit of the industry
Companies that can offer alternative blends, additions or technologies will be in a more competitive position in the coming years.
Furthermore, while there’s a danger of unintended consequences associated with a simple carbon rating for concrete, one could argue there’s a far greater risk associated with not seeking to limit carbon in concrete at all.
The LCC benchmark provides a catalyst to start discussion between clients, designers and suppliers and will hopefully help accelerate a shift in carbon intensity.
The benchmark was updated in September 2023.
Not the end, but the end of the beginning
One would think that after almost three years of dialogue, the discussion on decarbonising concrete might have been exhausted, but we’ve only just started.
This is due in part to the explosion of interest in the subject and the vast range of new ideas and technologies that are all contributing to potential solutions.
This is as well as the recognised urgency due to climate change.
There will be many more discussions and further guidance as we obtain more data, uncover more knowledge, and learn of new discoveries.
The routemap provides practical guidance to making the first steps in the transition to lower carbon concrete.
But there’s much more work to be done and many opportunities for the industry to meet the challenge.
The route ahead may be bumpy, but the journey is unavoidable.
We hope you’ll join us in finding the quickest way there.