Jobsite description

“Le Onze” residence in Chartres (France) is a 12 housing units, built both in accordance with an environmental new label approach (Positive energy building label with a low carbon footprint), and in favor of circular economy, with the objective to maintain balanced construction costs.
This eco-responsible project was supervised by the local Concrete Industry Federation and the Center for Studies and Research of the Concrete Industry.

CHRYSO expertise

The main stake of this project was the use of local materials in order to develop a circular economy approach. CHRYSO provided new admixture solutions, fostering the use of local sands and recycled aggregates in the production of concrete, in connection with the eco-responsible approach of this jobsite.

The structural concrete consisted of 30% of Recycled Concrete Aggregates from old building elements in the city of Chartres (both coming from ready-mixed concrete or precast concrete, such as walls, concrete blocks and stairs).


  • CHRYSO®Quad 563
  • CHRYSO®Quad 800
  • CHRYSO®Optima 372
  • CHRYSO®Omega 137 EMx

Project technical challenges

The concrete slab, composed of 100% Recycled Concrete Aggregates, required the development of a specific mix-design. A total of 80 tons of Recycled Concrete Aggregates were reused through this jobsite.

For the precast elements (walls and stairs), the challenge was to use local clay sands (0/4) with high absorption rate, in addition to 8% recycled aggregates (4/10). The concrete produced had a liquid consistency during 45 minutes, while maintening high strength performance superior to 15 MPa.

CHRYSO provided 100% of the admixtures on this construction site. Thanks to CHRYSO®Quad and Enviromix® technologies, a reduction of 360 tonnes of C02 was achieved on the construction site, decreasing the carbon footprint of 20%. “Le Onze” residence also obtained the E2C1 label (Positive energy building label with a low carbon footprint).

Project participants

Precast industrial: Spurgin Léonhart
Prefabrication Ready-mix supplier: Gallaud SAS
Real Estate Developer: Pierres & Territoires Eure-et-Loir
Project manager / architect: Yannick Mouton
Engineering Studies Office (E+ C- label): AET Loriot


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