Acoustical properties of aerated autoclaved concrete

This work analyses acoustic qualities of autoclaved aerated concrete (AAC). Three the most widely used types of AAC are chosen for the analysis: gas cement concrete, gas cement concrete with combined binder (Portland cement and lime), and foam cement concrete. The procedure and technique of the materials’ formation is presented in this work. The evaluation of acoustic qualities of AAC is based on the material’s air permeability and porosity (i.e., ratio of the volume of the interconnected pores to the total volume of pores). For this purpose the measurements obtained by an acoustic interferometer are used. The results of the experiment show that regression equations for the AAC types, which density ranges from 250 to 500 kg/m³, may be used to estimate the materials’ normal incidence absorption coefficient values, which depend on the air permeability and porosity. Results show that absorption coefficient of not specially treated AAC is rather low. According to the measurements obtained in a special reverberation room of 202 m³, a sound absorption coefficient may increase up to 0.6, provided that slits of Helmholtz resonator’s type are made in the slabs of AAC gas cement concrete with combined binder.