A trial in England funded by National Highways and led by Skanska in partnership with the National Composites Centre is comparing traditional steel reinforced concrete with a low carbon concrete reinforced with basalt fiber. The test is being run on a temporary road for construction vehicles.
Tarmac provided a traditional blended cement material for concrete and a low carbon alternative mix incorporating an Alkali Activated Cementitious Material in place of the cement. The carbon footprint of the new low carbon mix is up to 80% lower than a standard cement concrete.
The basalt fiber is non-corrosive, strong, and also decreases the carbon footprint of the materials used in the concrete. Malcolm Newton, director at Basalt Technologies, explained, “Basalt is a lightweight composite material consuming 62 per cent less CO2e than steel during its manufacture. It comprises a non-metallic inert material that does not corrode, making it more durable than steel. Basalt Fibre reinforcement is also 4 to 5 times lighter than steel, making it safer to handle, fix and transport with fewer lorry movements.”
The trial consists of four reinforced concrete slabs that were cast as part of a temporary road.
Slab A – Conventional concrete + steel reinforcement
Slab B – Low carbon concrete + steel reinforcement
Slab C – Conventional concrete + basalt reinforcement
Slab D – Low carbon concrete + basalt reinforcement
The research team is monitoring the slabs and test slabs were also sent to a laboratory for bending and shear testing. The test results will provide valuable information to allow the team to understand the structural behavior and benefits of the new, long lasting advanced materials, as well as demonstrating the sustainability of the materials.
Carys Holloway, technology programme manager at the National Composites Centre, summarized the project by saying, “This project, its learnings and test results, is critical to understanding the impact of low carbon concrete and advanced composite reinforcement systems to reduce embodied carbon for the construction sector. I am eager to witness the expected ease of planning out of the basalt fibre reinforced slabs for recycling and the potential that has for end-of-life scenarios.”