Valutazione speditiva della carbon footprint nella fase di fine-vita di un isolato residenziale. Analisi comparativa tra differenti scenari di demolizione e trattamento dei rifiuti basata su LCA e LCC / Environmental expeditive assessment of carbon footprint at the end-of-life phase of a residential buildings block. Comparative evaluation of different demolition and waste treatment scenarios based on LCA and LCC

The construction sector is responsible for approximately 50% of raw material extraction, 36% of CO2 emissions, and 35% of total waste produced annually. Therefore, more effective management of building end-of-life and immense quantities of raw materials stored inside the cities becomes a key element toward the ecological transition against climate change to a circular economy model. This research investigates the potential environmental impacts of carbon footprint and raw material extraction associated with the urban regeneration paradigm by replacement, analysing three emolitions and waste treatment scenarios through Life cycle assessment (LCA). In particular, each end-of-life stage of an urban residential block of Bologna built after the Second World War is investigated in order to identify the most environmentally efficient and cost-effective demolition strategies in these contexts. With a view to realising the material passport of the residential buildings block, the geometric data provided by the municipal georeferenced database and the constructive information sourced from archival research on constructions permits have been imported into Grasshopper. Subsequently, these data were used to evaluate and compare three different demolitions and waste treatment scenarios: the first (S1) involves the demolition and the landfilling of building materials; the second (S2) takes into account the selective demolition, the sorting of different materials, the recycling of main fractions of the demolition waste and the disposal of residuals; the third (S3) provides the same waste flows of S2 with the possibility of reusing demolition waste in situ for the new construction. The results quantify the advantage of an appropriate technique of selective demolition, which allows for reducing CO2 emissions of over 1000 tons and saving over 35,000 tons of new raw-material extractions in the face of contained increased costs (11.41%).