Construction and Demolition waste recycling for new sustainable materials production at high environmental efficiency

Management of secondary waste plays a crucial role for the achievement of sustainability targets of countries. For this reason, new models of development, based on the reduction of final disposal in landfills, are promoted regarding to those materials that may be reused and recycled (Vegas et al, 2007). European countries and their governments have implemented regulations to meet targets for materials recovery and reuse in order to reduce the effects of waste production and improve environmental protection following the principle of the sustainable development (World Commission on Environment and Development, 1987). However, national policies have shown to be generally inadequate to ensure the recycling targets proposed by the EU, still far to be achieved (Hendriks and Pietersen, 2000). Inert waste or construction and demolition waste (CDW) represent a relevant resource and its recycling and valorization can be placed rightfully in what today is called urban mining. Concrete industry is connected to a large use of natural resources, with an estimated world production of about 6 billions tons/year (ISO 2005). Italy produces approximately 30 million tons/year of CDW, mostly still destinated to landfill (....). Adoption of CDW, as alternative aggregates for concrete production, gains importance to preserve natural resources and reduce the need for disposal. Indeed, deposition of demolition waste, produced especially on active building sites, strongly contributes to landfill saturation (Stein et al., 1996; Manzi et al., 2013) and lead to considerable environmental concerns (Esin and Cosgun, 2007). CDW recycling is subject to continuous changes, not only by the regulation point of view, but also for what concerns the management and the techniques of CDW production, such as selective dismantling, treatment processes and the subsequent steps of characterization and use of the recycled materials (Marinkovic et al. 2010). The recent European Directive (2008/98/CE) imposes significant recycling rates (70% at 2020); therefore, for Italy, a significant improvement is required since it’s traditionally set back in recovery. As known, on the base of the UE Directive, reuse and recycling processes are encouraged in order to achieve higher levels of recycled waste both from a quantitative and qualitative point of view (Coronado et el., 2011). Article 11 of the Directive quotes that the Member States should take measures to promote high quality recycling of urban waste. In order to comply with the objectives of this Directive and move towards a European recycling society with a high level of resource efficiency, the Member States should take the necessary measures designed to achieve in particular the following targets: (a) by 2020, municipal waste shall be increased to a minimum of overall 50 % by weight; (b) by 2020, the preparing for reuse, recycling and other material recovery, including backfilling operations using waste to substitute other materials of non-hazardous construction and demolition waste, shall be increased to a minimum of 70 % by weight. A problem in reusing CDW is represented by their extremely variable nature. This is perhaps one of the most important and urgent problems to be solved for future implementation of secondary raw materials. Different treatment plants will produce very different materials depending on the context in which is located (Bonoli et al., 2008). Another deterrent to recycling is represented by the mistrust of quality and potential of recycled materials. Therefore, it’s important to test and certify their performances and suitability for specific uses. Presence of large quantities of crushed clay brick may render the recycled aggregates unsuitable for high grade use. This is, e.g., the case of wastes derived from earthquakes. However, concrete conglomerate is suitable for incorporating solid waste of different origin, while keeping acceptable performances. In literature several examples exist dealing with the use of concrete admixed with recycled materials, in which the natural inert is partially replaced by CDW products (Mymrin and Correa, 2007; Manzi et al., 2013; Coelho et al., 2013). Even if the attitude in the industry field is rather conservative, each step is important to ensure that these materials may become the marginal source of traditional materials and use coded. A continuous dialogue between the public and private, between governments and enterprises of production is the only way to handle a virtuous opportunities and prospects of the market. Experiments aimed at understanding the performance characteristics of recycled materials represents the first step to implement the use of that material and for instance to propose the adoption of a new specific material in a tender for road, build or railway construction. Literature reveals that one major barrier is the lack of data. Therefore, this paper presents a model which allows technicians to estimate C&D waste during the design stage in order to promote prevention and recovery. The types and quantities of CDW are estimated and managed according to EU guidelines, by building elements and specifically for an application in the in the construction of transportation infrastructures. This work has as objective the promotion of reuse CDW materials, analyzing the recycled materials from a treatment plant located in the province of Bologna in terms of performance, quality and cost, in order to encourage the formation of a short chain.