Sustainable, circular approach to construction

A new type of 3D printed concrete bridge has been constructed which follows in the evolutionary footsteps of the Striatus bridge showcased in 2021.

Holcim and Zaha Hadid Architects have collaborated for a second time on a new Phoenix design 3D printed bridge that contains concrete recycled from the first bridge which had no reinforcement.

Built in Lyon, France, the bridge comprises 10 tons of recycled materials including 100% recycled ECOPlanet cement.

­­­Holcim delivered the Phoenix project with a 25% overall reduction in CO₂ footprint compared to the Striatus using an updated ECOCycle circular technology with a proprietary concrete ink it had developed.

There were also improvements in the robustness of the digital design tools used and tighter integration with robotic concrete printing parameters, according to Zaha Hadid Architects. In addition, there was closer alignment with numerous structural design improvements and extensive calibration to improve efficiency of production to almost double the number of blocks in less printing time.

Block Research Group at ETH Zurich and incremental3D were partners on the project using the method that does away with the need for concrete reinforcement or post-tensioning. The construction method can also be used for floor slabs in high-rise buildings

Both the Phoenix and Striatus bridges were created without any waste at the site and are able to be deconstructed and used elsewhere.

Watch a time-lapse video of the Phoenix bridge construction.

Image: Block Research Group via

About the author

Desi Corbett

Desi is our weekly news journalist and the editor of Concrete in Australia magazine for 10 years. She has been heavily involved in all forms of engineering since 2013; part of a 30-year writing career across a range of subjects and media.