Sika solutions applied to recycled concrete in the La Vallée eco-district in Châtenay-Malabry

Since the fall of 2022, the new residents of Châtenay-Malabry have taken possession of the first housing in the La Vallée eco-district. Ultimately, it will be a district of nearly 2.200 housing units, 36.500 m2 of offices, around 15.000 m2 of shops, a college, a school group, an urban farm and a car park which will occupy the 20 ha of this former school site. Central.

Driven by the desire to create an eco-district that demonstrates the sustainable city in Ile-de-France, Eiffage Aménagement, in partnership with the Municipality, the Caisse des Dépôts and the Vallée Sud Grand Paris territorial public establishment, has implemented everything throughout this extraordinary project, an exemplary low-carbon eco-design and circular economy approach.

The LaVallée eco-district has thus involved spectacular achievements, starting with the phase of deconstruction of the Ecole Centrale buildings into 85.000 m3 of rubble.

Sorted, then crushed, 98% of the concrete and materials from the demolitions were reused on the site. Transformed into aggregates, they were reused either as underlays for the district's roads or, and this is the innovation, in new constructions with 30% recycled concrete, even pushing experimentation to the point of testing the construction of a building with 100% recycled concrete.

Eiffage produced 15.000 tonnes of high-quality recycled aggregates, necessary for the production of 40.000 m3 of concrete. The company chose the company Minier Béton to support it throughout this extraordinary project.

These made it possible to meet the expected requirements in terms of eco-design and circular economy, while also guaranteeing long rheology (1h30), robustness to water variations and facing quality.

The perfect quality of the concrete produced constitutes a first on this scale and overcame the reluctance inherent to innovative designs. The absorption rates observed for recycled aggregates are comparable to natural limestone aggregates and the quality of the materials produced on site present in all respects the characteristics required for the success of such a sustainable development project.

developer:

SEMOP (Society of Economics
Mixed Single Operation)
Châtenay-Malabry Parc-Centrale.

Promoters:

Eiffage Immobilier, COFFIM,
Kaufman&Broad and Icade.

Mastery of work :

The teams of each promoter
and for SEMOP:
- Urbanist architect :
  - Leclercq Associates
  - Landscaper: BASE
  - BET VRD: OTCI
  - AMO Sustainable Development: Even Conseil / Atelier LD / Suez Consulting.