Il recupero di materiali attraverso la demolizione selettiva. Un’analisi costi-benefici

From the point of view of Circular Economy and Urban Mining, cities represent real “mines of anthropogenic resources”: increasing the recovery of construction materials at the end of their useful life makes it possible to reduce the exploitation of primary resources and the production of waste. This contribution reports the results of a study that evaluates the possibility of reclaiming/recycling Construction and Demolition waste (C&D) by investigating the applicability of the selec- tive demolition process through a cost-benefit analysis. The selective demolition of a housing unit, contextualized in the Piedmont region, is examined and evaluated in two different scenarios: only demolition and demolition plus rehabilitation of the site, with the use of natural or recycled aggregates. For the reclaimed components and materials, two scenarios - sale for the reuse market or economic enhancement for recycling purposes – is assessed. The methodology used involves a temporal analysis of the demolition process, using a GANTT diagram, an economic evaluation, using Break Even Analysis and finally a sensitivity analysis, to assess the impact of the main items considered on the analysis model adopted. The results show that the optimal context in which to operate is one in which it is possible to subject to demolition materials equal to and / or greater in quantities of 380,658 kg, and that in which it is possible to use recycled aggregates for site remediation (presenting a BEP of 723,679 kg compared to that with natural aggregates equal to 1,181,879 kg). The present contribute also demonstrates how the large-scale adoption of Design for Disassembly, together with monetary incentive policies for the use of recycled aggregates, would allow to optimize the cost-benefit ratio in the selective demolition process.