LaVallée, an eco-neighbourhood showcasing our circular economy initiatives
As part of the future LaVallée eco-neighbourhood in Châtenay-Malabry led by Eiffage Aménagement, a large-scale circular economy demonstrator project was set up in 2018 to deconstruct the former site of the École Centrale Paris engineering school.
First, a resource assessment was carried out prior to deconstructing certain buildings to identify which fixtures and fittings could be reused (e.g. lights, doors, sanitaryware, handrails and emergency lighting units) to salvage as much as possible. Once regarded as waste to be processed, such materials are now seen as resources to make use of.
When calling for tenders for gutting and demolition, Eiffage Aménagement encouraged its partners to opt for the deconstruction of the buildings in question to improve the quality of the removed materials and products to be recovered. Crushed and recycled, 98% of the concrete recovered from deconstructing the buildings was reused on site.
Local partners serving the circular economy
Eiffage supports the work of RéaVie, an association founded in the Ile-de-France region by former construction professionals that helps safeguard hundreds of products, pieces of equipment and materials by promoting their reuse. For instance, RéaVie helped demolition company Boutté salvage as much material as possible – including suspended ceilings, plaster or glass partitions, doors, carpets and electrical components – from the 9 ha former PSA site in La GarenneColombes, where an office block built in 2013 was to be deconstructed.
The client had asked demolition companies to propose a circular economy-based approach. The schedule was adjusted to leave the deconstructed building until last. The preparation stage therefore provided the opportunity to integrate reuse into the project as much as possible.
In Châtenay, that approach involves gathering materials together on an experimental reuse platform called Solid’R, where they are collected, sorted, repaired and reconditioned before being sold to associations or low-income individuals. They can also be transformed in sewing and carpentry workshops, in a combination of the circular economy and solidarity.
Reusing materials and upcycling
The circular economy and design can go hand in hand, as proven by the projects delivered by B3 Ecodesign, a company acquired by Eiffage Construction in 2019 that specialises in modular construction using old shipping containers. Its processes are inspired by the automobile industry’s lean manufacturing approach to maintain production in line with demand, eliminating waste.
To do so, B3 Ecodesign uses a process called upcycling, which involves transforming waste materials into higher quality products. Upcycling converts shipping containers into modern designer housing, offices or retail outlets.
This circular economy-inspired construction method offers great flexibility, saves materials and time, and is architecturally pleasing.
Materials recycling and carbon storage
Chemist Antoine Lavoisier’s famous words “Nothing is lost, […] everything is transformed.” encapsulate Eiffage Route’s philosophy of making the recovery of materials a core part of its strategy.
Around 50 researchers, engineers and technicians are working on disruptive innovations in Eiffage Route’s research facilities in Ciry-Salsogne and Corbas in a bid to develop a competitive business based on recycling all natural resources and replace oilbased road surfaces with biosourced equivalents.
Additionally, RMN (Recyclage de Matériaux du Nord) and PréFerNord (Préparation de Ferrailles du Nord) set up a recycling platform at the Fretin waste management and recovery centre in the north of France. The 14 ha site has one section set aside for the recovery of deconstruction materials (RMN) and another for the recovery of combustion residues from household waste incineration plants (PréFerNord).
In order to reduce pressure on mineral resources and offer a CO2 storage solution, Eiffage is testing out a new, innovative method in LaVallée, where it is injecting pressurised CO2 into old concrete from demolition. Against a backdrop of dwindling quarry reserves and an unsustainable rate of sand mining, CO2 sequestration is a promising solution that captures carbon dioxide and greatly increases the recyclability of old aggregate, meaning less new aggregate is needed.