POSSIBILITY OF USING EXPANDED PERLITE AS TEXTURISING AGGREGATE IN LIGHTWEIGHT POLYMER PLASTERS - IMPACT ON THERMAL AND MECHANICAL PROPERTIES OF COATING

The final form of an external wall is made of many layers of materials. Each of them is important from the point of view of its properties. This work focusses on the possibility of modifying the thermal insulation properties of the finishing layer of the facade, the polymer plaster. To reduce the heat conduction coefficient, the standard marble texture aggregate was replaced with a light filler, expanded perlite. It is a highly porous material obtained due to the expansion process of natural volcanic rock. However, its use in building materials is associated with many complications resulting from its low mechanical properties and high water absorption. In this work, the appropriate selection of light fillers allowed the thermal conductivity coefficient to be reduced to as low as 0.125 W/mK. This value is six times lower than the reference sample. This was also accompanied by changes in the coating's impact resistance and adhesion to the substrate. The addition of expanded perlite significantly contributed to the deterioration of these parameters. Therefore, the amount of expanded perlite in the plaster recipe requires optimization to a level that maintains the necessary functional properties of the coating.