Circular economy and regeneration of building stock: Policy improvements, strategic partnerships and life cycle decision-making tools

The current European strategy of Green New Deal calls for the transition from the current linear economy (take-make-use-dispose) towards a circular economy (closed loop of materials), which aims at avoiding the generation of waste and reducing the extraction of raw materials, in order to preserve the planet's limited resources. To achieve this transition, the building sector, and in particular the regeneration of existing building stock, plays a crucial role, in fact it represents the first sector for the production of waste quantity, and one of the major sectors for the consumption of resources. However, at present time, the application of circular economy at building level, towards a sustainable circular building process, are thwarted by political and economic barriers. Not all countries have the same starting point and the same resources and that some of them are moving slower than others. In this context, the scientific communities have the duty to identify the correct strategies to suggest to the policy-makers, which have to define legislative actions to enable the transition. Consequently, the PhD research gives important support to the policy-makers, identifying a set of recommendations necessary to encourage a sustainable and circular transition in the building sector, in particular within the regeneration of existent building stock, defining the framework for a sustainable and circular building regeneration process. The recommendations are articulated to identify the important policies improvements, stakeholder networking and environmental and economic life cycle assessment tools for supporting the decision. The recommendations are useful at European level and, when necessary, some specifications are defined at the Italian level. Hence, the thesis result is an important support to the policy-makers, who want to change the legislation regarding the building sector towards circular economy and to the stakeholder of the building value chain who want to identify and open up new networking for the activation of sustainable circular profitable business. This thesis in particular focuses on the activation of sustainable circular dynamics during the building regeneration process, showing which are the current obstacles, which are the opportunity for the transition and, consequently which are the necessary improvements towards a sustainable circular process. The circular economy strategies are treated not only from the point of view of construction and demolition waste management (downstream approach) but focusing on the importance of avoiding the waste (upstream approach) in order to achieve a sustainable model. Therefore, the thesis encourages the strategies that aim to extend the service life of existing buildings (giving back new function and value), to repair and maintain the elements, to remanufacture and reuse the replaced products and, only finally, to recycle any demolition waste generated by requalification processes. Moreover, the thesis treats the fundamental issue to support the decision-making of circular strategies by environmental and economic sustainability assessment, within a life cycle perspective, in order to promote not only circular practices, but sustainable circular practices.