Conceptual design of a modular Expanded Polystyrene (EPS) formwork for sustainable prefabricated concrete slab

Abstract

European policymakers emphasize the critical need for a substantial renovation of the current European building stock, stressing the imperative to sustainably integrate energy and structural design. Consistent with the European objectives, industrialized construction and precast/offsite methods offer potential advantages in terms of time, cost, and quality for building renovation; along with the possibility of utilizing secondary raw materials, they enhance the energy performance of building products and advocate for environmentally sustainable solutions. This study presents the initial stage in designing a prefabricated concrete floor system, thermally and structurally high-performing, to be integrated into new and existing buildings. Specifically, the study outlines the design development of a modular element made with expanded polystyrene (EPS) for the construction of insulated floor systems with EPS lost-formwork (ICF - Insulated Concrete Form). This element ensures high and continuous thermal insulation without contributing to the structural resistance of the finished floor system. The process of designing, optimizing, and testing various design iterations is described. Materials and finished product requirements were identified, and numerical analyses and experimental tests were conducted. The main step involved the formwork mould, focusing on the shaping of joints, and evaluating the performance from a mechanical and thermal perspective. Field tests were also conducted, first on virgin EPS formwork and subsequently on a formwork containing a percentage of recycled EPS.