Concrete sorting
What is the RECYBETON project? The national RECYBETON project (RECYclage complet des BETONs), launched in 2012 and which ended in 2018, aimed to deepen knowledge on the reuse of materials from deconstructed concretes as elements of new concretes . This research has made it possible to radically increase the rate of incorporation of recycled aggregates into concrete, for example, in order to preserve natural deposits.récupération de béton The issue of standards Following the research carried out by RECYBETON, the European standards (Eurocodes) for building and civil engineering as well as the EN 206/CN:2014 standard for structural concrete for buildings and structures could evolve. Indeed, the standards allow 30% recycled aggregates and 20% recycled sands, whereas in reality, following numerous studies carried out, it is possible to put at least 50% aggregates and 20-30% recycled sand . Today, following numerous research works, the construction sector has been able to rebound to meet the various objectives of the ecological transition , and in particular in terms of recycling and recovery of concrete . Thanks to the reuse of deconstruction concrete aggregates, and in particular in the manufacture of new concrete, the sector tends to evolve from a linear economy to a circular economy, reducing the use of raw materials, but also CO 2 emissions. . Recycling concrete into concrete: it works! Launched in 2012, the National Research and Development Project RECYBETON* is nearing completion. For five years, actions and projects have been carried out to develop the recycling of concrete from deconstruction. The point with François de Larrard, scientific director of the project. The RECYBETON program was launched with the support of 48 partners, players in the concrete sector. What were his goals? This project was born from the desire to include the construction sector in a logic of sustainable development. One of the objectives was to demonstrate that concrete can be recycled like other materials. The challenge is both to reduce landfilling, by reusing some of the deconstructed concrete, and to save natural aggregate deposits. Each year, 17 million tonnes of crushed concrete could thus be reincorporated into new concrete compositions, to replace 10 to 30% of aggregates used in the composition of recycled concrete. The establishment of a circular economy around concrete would also make it possible to develop activity at the local level, by reducing the transport of materials. How does concrete recycling work, and what are the obstacles to its development? The first condition is to implement selective deconstruction techniques in order to sort concrete waste from other materials. The concrete blocks from the demolition are then crushed, before moving on to iron removal and screening. Additional steps, such as the detection and separation of unwanted particles, or even the splitting of composite aggregates (old cement gangue + original natural aggregate), can be implemented to purify the deconstructed materials.