Assessment of CO 2 Emissions by Replacing an Ordinary Reinforced Concrete Slab with the Void Slab System in a High-Rise Commercial Residential Complex Building in South Korea

The purpose of this study is to verify the environmental performance of the novel Void Deck Slab (VDS) system developed by the authors. The proposed VDS is a void slab system with enhanced design features that improve the constructability of the system through the elimination of additional works required to connect the void formers with the anchoring devices. The Life Cycle Assessment (LCA) technique was adopted to assess the carbon dioxide emissions of the void slab system with reference to the ordinary reinforced concrete slab. The system boundary of this study ranged from raw materials to pre-operation phase, in accordance with ISO 14044. The total CO 2 emissions of the ordinary reinforced concrete slab and the void slab system were 204,433.06 and 151,754.75 kg CO 2 -eq, respectively, which equated to about 34% less emissions for the void slab system. In the case of the ordinary reinforced concrete slab, moulds accounted for approximately 62% of CO 2 emission, followed by concrete (~34%). The main source of CO 2 emissions for the void slab system was concrete that accounted for ~50%, followed by moulds and deck plates that accounted for roughly 27% and 19%, respectively. In the case of the void slab system, void formers would enable a lower amount of concrete, as well as the self-weight of the slab. Besides, although the void formers filled a significant volume of the slab, the contribution to CO 2 emissions was less than 1%.