Experimenting with concrete demolition and its reuse in situ

Credits: Bellastock

As part of an ambitious program of urban renewal in Stains (Paris Region), the public housing office of Seine-Saint-Denis and the association of architects Bellastock experimented with in situ concrete recycling. Concrete shells from the dismantling of social housing dating from 1960 served to build new urban structures, such as benches and outdoor paving. The CSTB provided technical support to project stakeholders in support of the circular economy.

The public housing office of Seine-Saint-Denis (OPH 93) and the association Bellastock recycled demolition concrete from two apartment buildings to lay outdoor paving, make benches and planters, and build the walls of a technical facility. This initiative took shape in 2016 as part of a call for projects known as “Architecture of Transformation,” launched the previous year by Caisse des Dépôts and Union Sociale pour l’Habitat.

Technical, environmental and economic assessment

The CSTB provided technical expertise to the sponsors of this innovative project. It developed a best practices guide for reusing concrete that includes a series of checks and tests. These are essential for characterizing residual performance of the material and plan its appropriate reuse (floor coverings, bearing walls, etc.) in a cost-effective manner.

The CSTB also performed an environmental assessment of the structure, built from demolition concrete, throughout its life cycle. The environmental impact can be positive if you consider the appropriate reuse of the concrete as early as a building’s design phase.

Finally, the CSTB developed an economic analysis tool to compare traditional construction solutions with one based on concrete reuse. The results are economies of scale and optimization of the recycling process.


OPH 93, renamed Seine-Saint-Denis Habitat in December 2016, intends to continue this work for the entire urban renewal project in Stains. Caisse des Dépôts and Union Sociale pour l’Habitat are backing the development and reproducibility of the uses. This will help construction professionals, who must recycle 70 percent of construction waste by 2020.