HS2 project trials concrete printing

The High Speed 2 (HS2) train project is testing concrete 3D printing with a view to reducing construction time and carbon emissions.

Concrete flooring and other concrete structures on construction sites are made by pouring the substance into moulds or using concrete slabs. Heavy load-bearing areas are reinforced with steel. Printed concrete uses a 3D printing machine programmed to create concrete shapes. Compressive strength is added by using lattice internals without the need for manufacturing steel, thereby reducing carbon emissions. Graphene can also be added to further strengthen the concrete.

3D concrete printers use specialised cement that is 30% more eco-friendly than standard cement, The cement takes only a few minutes to dry. Printing can be performed onsite or done in an offsite workplace and transported.

The HS2 project is using printed concrete for retaining walls in tunnels. Rob Cairns, HS2’s innovation manager, says that concrete printing will contribute to greener construction. He explained:

“Innovation has a crucial role to play in cutting energy consumption and carbon emissions on HS2, so we’re looking for creative and fresh thinking on how to achieve this.”

A working group is looking at defining a new international standard for additive manufacturing known as ISO/ASTM 52929. This will cover concrete printed structures.

In the future, it is unlikely that most concrete flooring will be manufactured using 3D printers, but architects who want to create a textured look for concrete floors may add 3D printed structures to a floor.