Monolithic blocks of expanded obsidian as thermal insulating and acoustic building materials

Thermal insulating and acoustic materials and products are functional materials. The former are intended for thermal insulation, the latter - for creating acoustic comfort in buildings. The combination of these two groups of materials is due to the fact that they have much in common, starting with raw materials and technology for their production and ending with their structure and properties. A possible direction for increasing production efficiency may be the use of volcanic water-containing glasses as raw materials using new principles of expansion and pores formation. Expansion of obsidian is carried out at a temperature 1000-1200⁰C. At an expansion temperature above 1200⁰C, the main mass melts and granules/grains sinter. During sintering, both the size and shape of the pores appearing in the material change. The pores are mostly taking spherical form and becoming smaller. The obtained results show that the heat conductivity factor within 20-600⁰C is changed by 0.002W/m⁰K, that is from 0.004 to 0.006W/m⁰K. Sound absorption of monolithic blocks of expanded obsidian, in the frequency range 100-600 Hz, is from 16 to 54 percent, in the frequency range 600 to 1200Hz is 55 to 63 percent. Therefore, these materials with great success can be used as thermal insulating and acoustic building materials. Glass, which is 100 percent of the structure of these materials, does not deteriorate from exposure to chemical reagents, is not a beneficial environment for various microorganisms, fungi, molds.