Implementing Circular Economy (CE) principles is often considered as a key contributor to greater sustainability in the construction sector. As a major kind of infrastructure, there is an urgent need for transport infrastructures to be circular and sustainable. This dissertation answers how to implement CE in transport infrastructure projects, with the aim to achieve sustainability by 1) exploring the material-asset relationship connecting the ability of circular strategies to realize sustainability through a bibliometric analysis and literature review; 2) investigating the real case in a CE-representative city, Jingmen in China; 3) using the Sectoral Innovation Systems (SIS) approach to assess CE in the infrastructure construction sector in both China and the Netherlands to discern how key functions of SIS are related to challenges to CE introduction on the one hand, and solution directions on the other; and 4) proposing an analytical/implementation framework containing specific-related aspects of CE in urban transport infrastructure projects based on current literature.

Urban infrastructure development is one principal way people are transforming the natural world and their living conditions. It is important for humanity, but it can also cause major impacts to the environment, such as huge amounts of solid waste and CO2 emissions. Considering this, the circular economy (CE) is a promising alternative to the traditional “make, use, and dispose” linear economy model. However, as a strategy for sustainable development (SD), the CE is still in its infancy in the urban transport infrastructure sector. Therefore, this article aims to guide the implementation of CE during transport infrastructure projects. To achieve this goal, a literature review and case study were adopted as the research methods. After reviewing existing well-established CE frameworks, the iReSOLVE (implement, Regenerate, Share, Optimize, Loop, Virtualize, Exchange) framework is recognized as the most comprehensive one. Upon it, an analytical framework containing specific-related aspects of CE in urban transport infrastructure projects (which belongs to meso-scale) is proposed (coined as the 4Wh-iReSOLVE framework). The 4Wh means Who, When, Where, and What. The proposed framework offers insight into potential CE activities for transport infrastructure projects and assists in assessing the performance and impacts of CE of these projects to cover the gap of the neglected meso-scale. Ten circular viaduct project initiatives in the Netherlands are used as case analyses with the 4Wh-iReSOLVE framework. The results present the highlights of the circular viaduct initiatives in the Netherlands, with CE activities categorized into five groups (design-related strategies, general CE strategies, implementation, management, and related digital technologies and materials, as well as environmental sustainability). As verified by several experts of the projects studied, it can be concluded that the 4Wh-iReSOLVE framework is suitable for transport infrastructure project CE analyses and implementations. It can potentially be a suggested guideline in future policy documents.

Sustainable development and Circular Economy (CE) have drawn massive attention worldwide. Construction practices consume large amounts of materials, resources and energy. Sustainability and CE could play a big role in reduction efforts. However, the potential influence of both concepts on the planning and construction of large infrastructures remains unexplored. This paper investigates how professionals involved in a high-speed railway station project in the Chinese city of Jingmen envision the use of sustainability and CE for the planning and construction of the railway station and its surrounding areas. We reviewed policy documents and interviewed local professionals with the Triple Bottom Line (TBL) framework. The analysis reveals opportunities for improvement towards sustainability and the interdependence between the dimensions in the TBL framework for the railway station and its surroundings. The case shows that local professionals identify ample opportunities for improvement (presented as "sustainability ideas"), but none appear truly sustainable. These insights provide evidence that the hierarchical introduction of transition(s) creates a cognitive silo for local professionals when envisioning sustainability ideas. In the TBL framework, this study finds a useful and novel approach to break down the silos, because the TBL stresses the interdependence between the various sustainability dimensions.