Effect of concrete bare slab properties on heavy-weight floor impact noise in apartment construction

A legal mandate has recently been enacted in South Korea that requires pre-occupancy performance testing for floor impact noise in line with ISO standards (ISO 16283-2 and ISO 717-2). The minimum performance threshold has also been lowered to 49 dB for both light and heavy impact sources. To ensure adequate insulation against heavy-weight impact noise, the regulation stipulates that concrete slabs in newly constructed apartment buildings should have a minimum thickness of 210 mm. However, significant variability in impact noise insulation performance still persists, even in bare slab conditions. This study investigates how the physical properties of bare concrete slabs influence the performance of heavy-weight impact noise isolation at different frequencies in real apartment buildings. Non-destructive testing methods, including impact echo, ground-penetrating radar, and ultrasonic tomography, were employed to measure slab thickness, natural frequency, wave velocity, and elastic modulus. Field measurements were conducted in nine apartment units (four wall-frame and five moment-frame structures). The results revealed statistically significant correlations between heavy-weight impact noise levels in the low-frequency range of 50–160 Hz, slab thickness, wave velocity, and elastic modulus. Additionally, construction management strategies to reduce variability in heavy-weight impact noise performance in bare slab conditions were discussed.