XtreeE partners with the CNRS and the École des Ponts ParisTech for the industrialization of structural stamped concrete

The current study is part of a thesis which will enable the scientific and technological developments necessary for the design of innovative construction systems in reinforced (3D) printed structures..

Tests are currently being carried out within the Navier Laboratory (CNRS/École des Ponts ParisTech/Université Gustave Eiffel) – under the responsibility of Mr. Jean-François Caron, CNRS Research Director – for industrialization of the solution during 2024.

An innovation partnership to transform the construction sector

This project is part of a context of transformation in the construction sector and aims to accelerate the gradual transition from non-optimized massive concrete structures to thin or hollow concrete structures. XtreeE thus wishes to provide AEC (architecture, engineering and construction) players with a new reliable, sustainable and cost-controlled solution, responding to the economic and environmental challenges of the construction sector.

The aim of using fibers in concrete is to make it more resistant and versatile, while replacing traditional metal reinforcements. An alternative to reinforced concrete - subject to micro-cracks and whose preparation is long and tedious - fiber-reinforced concrete, which contains short fibers, is a proven process but whose manufacturing cost remains high and implementation difficult. The research topic here focuses on the 3D printing of long fiber concrete composites – mineral counterparts of FRP ( Fiber Reinforced Plastics). And for good reason, 3D printing and robots have changed the situation by making it possible to produce concretes with a much higher fiber content than in current fiber-reinforced concretes, which only include 3 or 4% (maximum 10%). ) on average. The development of such a material will make it possible to build structures more resistant to traction, wear and shock, fire or even abrasion, while taking advantage of the greater freedom of shapes and the reduction in the quantity of material that 3D printing allows in the design of works.

To do this, XtreeE collaborates closely with the Navier Laboratory, notably via its project Build’In – born from a reflection by the Ecole des Ponts ParisTech on the environmental impact of the construction sector – aiming to support the transformation of the construction sector through digital technology. The Build'In platform is the winner of a project Sesame Sector France 2030 through which the State and the Île-de-France Region support the structuring of strategic sectors by relying on the scientific and technological capacities of higher education and research establishments. It is thus equipped with 3 large robots, one of which manipulates a two-component printing system developed by XtreeE.

Scientists and industrialists: effective cooperation for the development of additive manufacturing

It was in 2016 that XtreeE and its partners began to bring together their work to develop a long-fiber concrete printing process, which was previously non-existent. As such, the 3D printing specialist is co-financing with the CNRS the thesis of one of its collaborators, also a doctoral student at the Ecole des Ponts ParisTech, on the said process. A proof of concept has already been carried out and demonstrated tensile strengths similar to reinforced concrete.

The current study is part of a process of scientific research and exchange of experiences between XtreeE, the École des Ponts ParisTech and the CNRS for the development, ultimately, of an industrial prototype from 2024. For the occasion, a new print head specific to fiber-reinforced concrete was developed and now equips the Build'In platform and the XtreeE research center. The aim is to design constructive systems in reinforced printed structures such as complex structures, assembly parts, light covers, optimized floors and crossings.

This solution will be added to the platform catalog XtreeE “Printing-as-a-Service” which provides a set of certified products and digital support tools to facilitate architectural design and the production of 3D printed parts.

Develop large-scale 3D printing, in France and around the world

With a multidisciplinary team made up of architects, engineers, materials researchers, roboticists and Compagnons du Devoir, XtreeE also regularly welcomes interns from engineering and architecture schools, from different disciplines and origins. Building on this academic anchor (three of XtreeE's employees are doctors or doctoral students), the company created in 2015 has increased partnerships – in France and internationally – with research institutes and universities.

Recently, a new printing unit was installed in Canada within the School of Higher Technology (ETS) of Montreal. It brings the number of connected 13D printing units to 3 and is more generally part of XtreeE's strategy of structuring a network of more than 50 3D printing units on a global scale by 2025. Indeed, after installing a printing system at the École des Ponts ParisTech in 2018, the French company quickly equipped numerous universities internationally – Cornell University ou Texas Tech University in the United States – and research centers such as the Empa Institute in Switzerland, for which it develops different 3D printing systems adapted to their needs. A strategy pursued with a view to contributing to the renewal of the resources available within these establishments and enabling students and researchers to be ever more innovative and creative, in order to accelerate the development of the ecosystem around 3D printing and the digitalization of construction.

With the aim of responding to the challenges linked to the building and public works sector, the research carried out by XtreeE and its partners should ultimately make it possible to build low-carbon, optimized, tailor-made elements at a lower or equivalent price (taking into account all direct and indirect costs) to those of traditional construction.