Acoustic performance of social housings in Brazil: Assessment of lightweight expanded polystyrene concrete as resilient subfloor

Abstract

The vast majority of multi-story buildings in Brazil are not designed with acoustic treatment for impact sound insulation due to the high cost of floating floors, applied only in housings for medium and high-income populations and neglected for social housings. The use of EPS in lightweight concrete to insulate impact sound could become an extremely viable alternative in technical, economic and environmental terms. However, few studies have investigated the properties of lightweight concretes as acoustic insulators and none has investigated the lightweight concrete performance under mechanical stresses in the construction and use phases of buildings. The research aimed to investigate the equilibrium between mechanical resistance and acoustic insulation for lightweight concrete with different contents both in the laboratory and in the field. In the laboratory tests, a lightweight concrete with incorporation of 50% of EPS and density of 1100 kg/m3 achieved this optimum equilibrium, especially at frequencies above 500 Hz. In the real building, the EPS lightweight concrete with density of 1100 kg/m3 reached only L'nT,w of 74 dB, but this value is still within the minimum performance level according to Brazilian standard. The system showed no reductions in sound pressure levels at medium and high frequencies mainly because it was adhered to reinforced concrete slab, increasing sound transmission at high frequencies by reducing sound insulation of the mass-spring-mass system provided by the EPS lightweight concrete. The research results were promising, giving viability signs of applying EPS lightweight concrete subfloors in social housing in Brazil at a low production cost.