Thermal properties of natural hydraulic lime-based plastering repair mortars with expanded glass granulate.

Unsatisfactory environmental impact on old building operation leads to an effort to amend renovation and restoration process pointing to the reduction of energy consumption caused by heating and cooling. Large part of historical building envelope is represented by valuable highly decorative facades with insignificant thermal insulation function. The necessity to reduce heat transfer via building envelopes while maintaining aesthetic values of historical decorative facades is enables application of renders with improved thermal insulation performance. However, the newly developed materials for facade repairing must be compatible with the old ones, originally used in the past. In this study, natural hydraulic lime-based plastering mortars were tested. Natural silica sand (SA) used in the reference samples was replaced by an expanded glass granulate (EG) in the selected volume ratio. The basic structural properties and thermal properties in dependence on moisture content were studied. The results show considerable drop of thermal conductivity values with the increasing share of EG aggregate. The developed materials were categorized in accordance with the thermal insulation plasters standards as the thermal insulation mortars of T2 type. [ABSTRACT FROM AUTHOR]