Sound-absorbing properties of porous glass ceramics from zeolite-containing rocks

Introduction. Sound-absorbing systems are widely used in construction, reconstruction, repair of industrial and civil facilities, as well as in mechanical engineering. The most affordable and widely used systems are those using porous materials. The influence of the type, size, nature of pores, as well as phase composition of porous glass-ceramic samples obtained from zeolite-containing rocks on its sound-absorbing properties was established. Materials and methods. The results of experimental studies were obtained by the impedance method, as well as by methods of X-ray phase analysis, light microscopy, X-ray microtomography, etc. Results. Porous glass-ceramic materials with average density grades D250 and D300, compressive strength class B3.5, thermal conductivity coefficient from 0.066 to 0.079 W/m∙°C and recommended maximum application temperature up to +850 °C were investigated. The total porosity of the tested specimens of glass-ceramic materials was from 87.7 to 90.1 %, and the number of open pores from to 18.3 %. The sound-absorbing properties of porous glass-ceramic specimens are directly dependent on the open porosity of the material. With an increase of this indicator from 4.5 to 18.3 %, the sound absorption coefficient of the material increased 1.5–2 times, depending on the range of sound frequencies. Conclusions. Porous glass ceramics obtained from zeolite-containing rocks have good physical and mechanical properties and a high application temperature (at least +850 °C), and with a high open porosity index, it can be recommended for application as sound-absorbing materials in construction and mechanical engineering facilities.