Enhancement of the thermal performance of voided concrete slabs filled with expanded polystyrene

Incorporating voids to enhance heat transfer properties in building structures is an innovative approach for evaluating the structural and physical performance of integrated building components. While voided lightweight formers reduce material density, they may compromise the member’s load-bearing capacity, making mechanical resistance a critical factor in their development. This study investigates existing lightweight concrete slab systems that incorporate air voids. Additionally, considering the increasing adoption of these systems worldwide, it introduces a new advancement in lightweight technology: concrete slabs voided with expanded polystyrene (EPS). The thermal properties of these slabs and those incorporating plastic void formers were compared. Experimental results revealed comparable thermal performances for samples employing EPS and plastic void formers. Numerical simulations were conducted to validate the experimental data and estimate the thermal performance of voided concrete slabs in roof structures. These analyses identified the impact of thermal conductivity parameters on the energy efficiency of real-scale components for building applications. When employing EPS voids, the equivalent thermal conductivity ranged from 0.929 W/(m·K) to 0.834 W/(m·K), depending on slab thickness, which amounts to a reduction of up to 47 % compared with solid reinforced concrete. Furthermore, cost analysis demonstrated the competitiveness of both technologies, with potential cost reductions of 4.6–7.9 %, positioning them as promising solutions for the construction sector.