Jackson Civil Engineering brought together two suppliers – one with a carbon negative aggregate and one with a cold foamed bitumen asphalt – to generate CO2 savings of up to 90% compared with a traditional hot AC20 asphalt mix.
The mix was used to construct a new cycle path being built for Birmingham City Council as part of the Bromford flood alleviation scheme.
Jackson supply chain manager Andy Lusher said: “The cycle path provided an opportunity to look at the original design and ask ourselves how we could do this in a more carbon-friendly way. We brought our supply chain together to use their expertise and come up with a solution that was truly innovative.”
Partners on the trial scheme include OCO Technology, which has developed a carbon negative aggregate made from waste material from the treatment of flue gases from waste incinerators.
“With Zero Carbon being a global target, the construction industry must source alternative, more sustainable products, to not only reduce the carbon footprint but to preserve the finite reserves of natural aggregate in the UK,” said OCO technical director Stephen Roscoe.
Surfacing specialist Toppesfield was also central to the project. Its team took the OCO product and mixed it with ToppFoam, its own cold foamed bitumen asphalt that incorporates recycled aggregates.
Toppesfield technical director Paul Phillips said: “Working on the Bromford project has given us an opportunity to look at where we can reduce carbon in our operations further. Our strength and resilience tests show the new cold foam mix is fit for purpose and as we strive towards Net Zero, we expect it to become the surface mix of choice for future path and light use road construction projects.”
Phase I of the 2.5km cycle path has been built and work on the remainder is expected to start in April. It is projected that up to 70 tonnes of CO2 could be saved on its entire construction.
Cemfree
A further 30 tonnes of CO2 was saved using Cemfree concrete to bed and surround the kerb stones along the path. This product was developed by DB Group and produced by Accumix Concrete.
DB Group commercial manager Tony Sheridan said: “This project is another example of the market-driven demand for real world applications of sustainable construction products as the general public’s concerns over carbon emissions and climate change are felt.”
Andy Lusher said that this trial had given Jackson confidence to specify low-carbon concrete and asphalt in future projects.
“We’ve learnt lots of lessons from this trial and we know we can do something that pushes the boundaries but only with the full support and buy-in from our supply chain partners,” he said.
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