Study of sound absorption and reflection coefficients and thermal conductivity of porous composite material obtained from household glass waste and burnt rice grains husks

  • 1 Institute of Metal Science, Equipment and Technologies with Hydro-and Aerodynamics Centre “Acad. A. Balevski” at the Bulgarian Academy of Sciences, Sofia, Bulgaria
  • 2 Sofia University “St. Kliment Ohridski”, Faculty of Physics, Department of Nuclear Engineering


The coefficients of sound absorption and reflection in the frequency range up to 2 kHz, here respectively 0.2 and 08, as well as the coefficient of thermal conductivity, here below 0.027, of a new porous composite material were studied. The material was obtained from ground household glass waste and rice grains husks burned at temperature from 4000C to 7000C. The results show that the material has good sound reflectivity and low thermal conductivity, which makes it suitable for the manufacture of modules for thermal and sound insulation.



  1. D. Yordanov, Z. Tsonev, G. Yordanova, Characterization of silica material from magnesium and lead treated with agriculture waste, Ind. Technologies, II (1), 29-32 (2015)
  2. F. Fahy, Foundation of Engineering Acoustics, Elsevier Academic Press, San Diego (2005)
  3. D. Russell, Absorption Coefficients and Impedance, Science and Mathematics Dep., Kettering University, Flint, MI, 48504.
  4. ASTM E1225. Standard Test Method for Thermal Conductivity of Solids Using the Guarded-Comparative- Longitudinal Heat Flow Technique

Article full text

Download PDF