Prestressed segmental slabs in reclaimed concrete or stone: a systemic and effective solution for sustainable floors

Abstract This paper proposes a new structural slab system, based on a prestressed assembly of reclaimed concrete elements, as a scalable solution to reduce resource extraction and embodied carbon in the construction sector. The system assembles square voussoirs sawn from existing buildings into prestressed beams designed for typical spans and loads in buildings. Standardized dimensions, early-stage design tools, and reduced dependence on concrete strength allow for design adaptability and efficient implementation. This systemic approach aims to facilitate reuse without relying on coordination between demolition and construction sites. Full-scale four-point bending tests, conducted to validate the structural behaviour, showed that the beams remained uncracked under service loads and displayed a nonlinear and mostly elastic response in the cracked state. The prestressing and the low creep of reclaimed concrete improve long-term stiffness. Life cycle assessment results indicate that greenhouse gas emissions could be reduced by approximately two-thirds compared to conventional reinforced concrete slabs.