In the context of demolition programs which are growing rapidly, particularly in the framework of major urban projects, ECOREB (Eco construction with concrete recycling) aims at dealing with recycling issues in the field of construction waste for the future sustainable city. Among the building wastes, only a part of concrete from demolition is currently recycled, mainly for road construction. Recovery of all of these materials as components for the production of recycled concrete is now opening up new environmental, economical and technological prospects but needs to overcome scientific and technological brakes.
Reuse of recycled aggregates from demolition / deconstruction can limit the extraction of raw materials and thus contribute to the preservation of natural aggregates. It deals thus primarily with environmental issues. The use of recycled aggregates for the development of new concrete is part of a commitment to sustainable development, partly due to expectations of the “Grenelle de l’Environnement” in France and European regulations. Note also that waste management of building is also a growing market.
ECOREB is an industrial research complementary to the National Project RECYBETON. It proposes overcoming fears about the use of recycled aggregates from concrete in the building industry to produce new concretes, using largely experimental results. ECOREB aims, also, at developing new tools dedicated to the study of the water demand due to the presence of cement mortar embedded to aggregates. Moreover ECOREB will make possible the characterization of the interfaces quality between (1) the new concrete and the recycled aggregate and (2) the recycled mortar and the natural aggregate. It also aims at providing a tool for predicting recycled concretes characteristics and especially their behavior under external stresses (mechanical loads, snow, corrosive atmospheres, …) and under internal stresses (shrinkage, change in humidity or heat of concrete hydration ) and to establish empirical relationships between mechanical parameters and indicators of sustainability in relation to the microstructure which depends on water demand.
To achieve these objectives the scientific program is divided into three technical tasks that interact and complement each other.
The first “Water and recycled materials” provide recommendations on the formulation of concrete made from recycled materials, the curing of young concrete and the plastic shrinkage phenomenon as well as the associated cracking.
The second “Study of mechanical behavior of recycled concrete under static, cyclic, creep and relaxation loadings” will characterize the mechanical behavior of recycled concrete and establish empirical models incorporating microstructural effects. These models will be used by building industry actors to predict the lifetime of the recycled concrete.
The third task “durability” will evaluate the freeze / thaw resistance and long-term behavior of concrete recycled regarding to corrosion, chlorides migration and steel corrosion risk. Durability indicators will be assessed. Water and curing effects will be treated.
Results of ECOREB will lead to a breakthrough on the reuse of demolished concrete as components of new concrete and, ultimately, to a way in which the use of recycled aggregates in concrete will become part of everyday practices.