Concrete a recyclable
State of play A distinction must be made between two types of recyclable or recoverable concrete flows: those resulting from manufacturing processes ( precast factory or ready-mixed concrete production units), as well as feedback from construction sites those resulting from deconstruction .récupération de béton Concrete waste generated by manufacturing has several origins: fresh concrete waste, hardened concrete waste , manufacturing scrap and site returns. They can be reintegrated in situ (precast factory or ready-mixed concrete production unit) for the manufacture of new products, or recycled once hardened, without the need for additional sorting, in crushing facilities. 80% of deconstruction concrete already recovered There are currently several outlets for concrete resulting from the deconstruction of structures and buildings. They are mostly recovered , then processed in dedicated facilities (crushing, screening, additional sorting, etc.), in order to then be recovered for backfilling or road applications (capping layer, roadbed layers, foundation concrete, etc. ) ). All of these valuations represent a market of 14.5 Mt, or 80% of the tonnage of deconstructed concrete, corresponding to an equivalent saving in natural resources . The remaining 20% is now directed to inert waste disposal facilities (ISDI) . Indeed, demolitions without sorting or the distance between the sites and the treatment facilities do not always allow an economically acceptable recovery. This is particularly the case in rural areas, unlike urban areas where almost all deconstruction concrete is recycled. Sorting, a mandatory step Sorting is essential to separate concrete from other materials (plaster, PVC , reinforcement, etc.) during the deconstruction of buildings or infrastructure, then during the treatment of waste on sorting and grouping platforms. Sorting techniques are improving regularly and selective deconstruction approaches should become ever more systematic . The waste diagnosis before deconstruction, now compulsory for large buildings, contributes to this optimization of the quality of sorting. For its part, in order to facilitate deconstruction operations and thus better recover or even reuse products, the concrete sector is committed to developing the design of construction systems and products. Since January 2012, the National Research and Development Project "RECYBETON" aims to optimize existing processes to use: the fine elements of crushed concrete in the manufacture of cement or as filler or addition in the production of new concrete, concrete aggregates crushed in the manufacture of new concrete, with the aim of complete recycling of deconstruction concrete. The results of this project were published in 2018.