l'ACV: première étape d'une valorisation multicritère du sable recyclé dans le secteur de la construction

Abstract

In the context of sustainable development, the construction industry trends towards by-products valorization in order to decrease its environmental impacts. However, the use of these alternative materials does not automatically improve the environmental performance since its recycling processes require additional burden to the system. Subsequently, it is important to determine the recovery conditions that prove environmental benefit, and also the economic profitability to increase the implementation chances in the current market. With this in mind, this study focuses on the recovery of recycled sand (SR) in replacement of natural sand (SN) in masonry mortars. SR is the sandy part issued from the recycling of ready-mixed concrete leftovers; This part is usually discarded. Environmental life cycle analysis (LCA) is proposed as a decision-making tool prior to any in-depth technical study in order to check whether this recovery induces an environmental benefit. Several SR substitution rates are evaluated showing that SR can be an ecological alternative to SN. Some compositions even cancel out the resource use indicator. Furthermore, LCA allows the optimization of production activities and highlights the edge of SR over other alternatives. From an economical point of view, life cycle costing (LCC) studies are performed to assess the application; Several economic scenarios are studied by varying the price of SR compared to SN. The results show an economic interest in all considered scenario. Once the environmental and economic benefits are proven, a technical study of the proposed assembly mortars is carried out proving the overall soundness of the valorization process.