A decision support model for analysing the reuse potential of hollow-core slab floor components

Abstract

This thesis ‘A decision support model for analysing the reuse potential of hollow-core slab floor components’ describes the development of a decision support model to investigate the reuse potential of a structural building component. For this research, the hollow-core slab floor component is chosen as the structural building component to be reused. The main research question to be answered is: ‘How can various methods and knowledge be integrated into a decision support model for deciding on the reuse potential of a hollow-core slab floor component to close the material cycle?’ The ambition of the Dutch Government is to transform from a linear economy to a circular economy, whereby waste is excluded and products will remain in the system for longer at a high-level value. However, the barrier preventing the implementation of high-value reuse is the lack of knowledge to understand the opportunities and the impact of high-value reuse. It appears that the reuse of hollow-core slab floor components is not yet common because of the uncertainty and risks involved in the reuse of these components. The component has various properties that are advantageous for the reuse of these components, such as the lightweight of the component, the long technical lifespan and the standard dimensions of the component to use it all over the world. By way of contrast, a concrete topping, bonded connections, and the high costs for the deconstruction of the components are seen as barriers to reuse the components. However, it has been investigated that it is possible to use these floor components for longer than they are currently being used. Still, this is only possible if there is a full understanding of the reversibility, the reuse options, and how to increase the reuse potential of these floor components. The ‘reuse potential factor’ is a factor between 0 -“waste-like”- and 1.0 -“resource -like”- and it is defined as a factor measuring the ability of a construction component to retain its functionality after the end of its primary life related to the economic and environmental impact of reusing this component. Therefore, the factors related to the quality – qualification factors – should be tested and the factors related to the economic and environmental impact – quantification factors – should be determined.
There is a demand for a model that tests the performance of building components to assess the reuse potential of building components at the end-of-life stage. It is about making a decision about the consideration of the use of a new manufactured structural building component or a reused structural building component where the impact on the environment and economy remains limited. The first step to measure the reuse potential factor of the floor component is the reuse analysis in which the quality of the reused component should be determined based on the qualification factors. The qualification factors to be tested are the lifespan performance, technical performance, functional performance, aesthetical performance, and additional performance. The second step is the reuse evaluation where the ‘costs’ of the reused component are calculated based on the quantification factors. The quantification factors are the environmental impact costs and the economic impact costs based on the LCA and LCC tool. The decision support model analyses the relationship between the qualification and quantification factors of the reused hollow-core slab floor component and to compare the outcomes with the factors of a new manufactured hollow-core slab floor component. The qualification factors of the existing floor component are tested to see if they meet the required performance of the new construction project, or if the component must be adjusted. This will influence the ‘costs’ and the reuse potential factor. This model can be a tool that positively contributes to the ambition of the ambition of the Dutch Government about the transition to a circular economy.