Environmental impacts of Design for Reuse practices in the building sector

Actors of the construction sector are facing the challenge of reducing their carbon footprint and ideally reaching carbon neutrality. Reuse of structural elements made of concrete is of particular interest, given the large use of this material worldwide and its high environmental impact. Reusing constructive concrete elements is however challenging, particularly because connections between concrete structural elements are difficult to disassemble. It is then worth designing reuse techniques for concrete load-bearing elements and to verify their environmental performance using comprehensive methods such as Life Cycle Assessment. Based on the Design for Reuse concept, this article assesses the environmental impacts of a reusable structural portal frame constitutive of a concrete building and compares it to a traditional design with new materials. It relies on data collected through an experimental protocol of reinforced concrete structures construction/deconstruction/reconstruction using hydrodemolition. Impact scores are significantly reduced for all environmental categories after a first reuse cycle, both at the scale of a portal frame or a building. Concrete, and particularly high performance concrete, has durability qualities allowing to undergo several usage cycles. The effectiveness of environmental benefits however depends on functional downgrading and material losses. Guidance should then be provided to insure that future reuse practices will actually provide the expected benefits. This has to be conducted in parallel to full-scale experiments of load-bearing elements disassembly to estimate the realistic rates that can be obtained when deconstructing a building.