The contractor building the tunnels approaching Euston for HS2 is using 3D-printing for some of its concrete structures, in the UK’s first live deployment of the technology.
Printing concrete with computer-operated robots will enable the contractor to make structures on-site, instead of transporting them as pre-cast slabs by road before being assembled and lowered into place by large cranes.
Also, where HS2 construction is happening besides a live railway, it offers an opportunity to deliver works without disrupting the travelling public. This is because a robot will print the reinforced concrete, enabling construction to continue and trains to run at the same time. Previously work would have taken place overnight after trains have stopped running, potentially disturbing the local community, or would have required the suspension of services to ensure safe working.
Using a computer-controlled robot enables the reinforced concrete structures to be printed with a strengthening unique internal lattice structure, which not only significantly reduces the quantity of concrete required but also cuts waste.
The 3D printing was developed by Worcestershire-based ChangeMaker 3D, and the concrete mix will include microscopic strands of graphene only several atoms thick to replace traditional steel reinforcement.
The end result should see less concrete used at the Euston tunnel site — which apart from emitting less CO2 in concrete production, also means a lot fewer lorries delivering the concrete mix to the building site.
Proof of concept trials are due to begin in Spring 2022.
Crossrail also used 3D printing, although in their case the technology wasn’t ready for the concrete itself to be 3D printed, so they used the technology to 3D print the concrete moulds instead.