Advanced, high-performance thermo-insulating plaster

Abstract

The main purpose of many current studies regarding energy efficiency is the improvement of the thermal resistance of buildings. To fulfill this goal, the development of advanced insulating materials, to be incorporated in the building envelopes, is imperative. Aerogels are ultralight porous materials typically produced via the sol-gel process followed by supercritical drying of the wet gel. They exhibit very high porosities and a mesoporous-macroporous structure which endows aerogels with extremely low thermal conductivity. This makes them ideal candidates for ambient thermal insulation applications. However, the cost for aerogel insulation is considerably higher than the one of standard insulation products. In the present work, highly porous aerogel-like materials based on silica and commercial novolac resin were developed and added to common mortars. The prepared materials were dried under ambient pressure to minimize the manufacturing cost. The bulk density of silica quasi-aerogels was 0.03 g/cm³–0.09 g/cm³ and that of the novolac resin samples 0.09 g/cm³–0.21 g/cm³. The aerogels were incorporated in mortars and cured for 28 days before measurement of thermal conductivity. The values of the thermal conductivity coefficient of the measured samples were 0.047 W/m K–0.058 W/m K for the silica reinforced mortars and 0.036 W/m K–0.044 W/m K for the novolac reinforced ones.