The first subject “technologies and processes” will focus firstly on “sorting” aiming to separate the various inert materials generated by deconstruction and hence avoid mixing them with other materials. Once the concrete is separated from the other wastes, ways to improve the separation of its various constituents, in particular to extract fine particles, will be explored. Processes will be considered using these components to make new concrete or even new hydraulic binders. Assessment for cement potential of fine from crushed concrete, by incorporation in the raw mix and by mixing it with clinker, will be particularly studied.
The second subject will focus on “materials and structures.” It will first determine an appropriate characterization process of recycled aggregates to control the parameters that will play an important role in properties of the material made using these recycled aggregates. The impact of recycled aggregates on the behavior of fresh and hardening concrete will also be studied. As such, it is planned to carry out studies on the rheology of fresh concrete recycled, on the cement-superplasticizer-recycled aggregate compatibility, and on the plastic shrinkage behavior. Investigations on the mechanical behavior of recycled concrete in its hardened state will also be undertaken: behavior of recycled concrete in tension/compression, structural behavior of beams in bending/shear under monotonous and cyclic loadings, adhesion between the recycled concrete and steel reinforcements, delayed deformations: creep, relaxation. Other research work on the durability of recycled concrete will complete this subject: hydration and evolution of the microstructure in concrete, the parameters controlling reinforcement corrosion, carbonation, migration of chloride ions, drying shrinkage of recycled concrete, frost resistance, and durability indicators. Finally, fire resistance of recycled concrete will be studied.
The third subject will deal with aspects related to sustainable development. The development of recycled concrete also requires a socio-economic study. Accompanying measures need to be determined to create an effective and complete concrete-recycling program in connection with various potential markets (roads, buildings, etc. ….). This will depend on local constraints and local resources of natural or recycled aggregates. This study will be based on a detailed analysis of the network of collection centers for demolition materials and the areas where they are consumed. A more detailed study will be carried out in certain areas (Paris, Lyon, Lille and Toulouse) to assess the socio-economic development of this sector. The achievement of environmental product declaration (EPD) and of life-cycle assessment (LCA), the study of the washing water of recycled aggregates and the leaching / percolation process of recycled concrete will complete the analysis of the environmental and health impacts that new products made using recycled concrete aggregates could induce.
A transverse subject will deal with standard and normative issues to provide an efficient and coherent means of applying the obtained results. The “development” subject will be specifically dealt with from the beginning until the end of the project and will also be considered as a transverse subject.