Stability Relevant Properties of an SiO2 Aerogel-Based Rendering and Its Application on Buildings

Abstract

Aerogel-based renderings and plasters have been spreading throughout Europe for nearly a decade. Several national and EU-funded projects have addressed this interesting building product, both at research level within academia and at application level within R&D of renowned industrial enterprises. At present, a number of investigations into the hygro-thermal, chemical and application properties of a commercially successful aerogel-based rendering and its main ingredient, SiO2 aerogel granules, have been undertaken. Immersion in water showed that even under harsh circumstances water does not enter the aerogel granules, but rather accumulates in the porous phase surrounding the granules. A further immersion in calcium hydroxide at different temperatures did not affect the aerogel granule either, which indicates the robustness of the granules with respect to their exposure to moisture and chemical deterioration emerging from the construction materials the rendering is applied on. An executed application to a historic building with a structured finish, and without any reinforcement mesh, showed the advantage of a versatile applicability of this rendering when the external appearance and visible details of a façade must be kept unchanged. The investigation is rounded off by an infrared picture taken on a cold day showing the thermal influence of the aerogel-based rendering, and its effectiveness for reducing heat loss in buildings.

Increasing Water Absorptivity of an Aerogel-Based Coating Mortar in Subsequent Wetting and Drying

“…However, one could expect higher stresses than only one cycling to cause such level of deterioration. Additionally, the study presented by Stahl et al [ 2 ] showed that hydrophobized aerogel granules could resist harsh and alkali environments for longer periods without any sign of significant damage due to water intrusion inside the aerogel granules. As for the third explanation, the observations could also connect to the pore structure and moisture distribution in the samples before and after each wetting and drying cycle.…”

“…Because of their superior thermal insulation properties, ACMs provide new technical solutions for the energy retrofitting of uninsulated building envelopes, particularly in listed and culturally valuable masonry buildings [ 1 , 2 , 3 ]. For many of the listed buildings, restrictions related to the preservation of character-defining elements, admissible thickness of building envelopes, and existing (moisture-related) damage to the construction, reduce the number of possible retrofitting measures [ 1 , 4 ].…”

Current Trends in Aerogel Use in Heritage Buildings: Case Studies from the Aerogel Architecture Award 2021

“…A more recent new use of silica aerogels is the creation of structured façades in historic buildings using silica aerogel renders [24,25]. This innovative approach demonstrates the versatility of such renders and their potential for reducing the energy demand of historic buildings without impacting their appearance if the existing render is not under heritage protection.…”

Effects Of Silica Aerogel Produced From Boron Wastes To Compressive Strength And Thermal Performance Of Environmentally Friendly Bricks

“…The most used type of aerogels, which have different types, is silica aerogels [36]. Silica aerogel, which is a nano structured material is a unique construction material with high porosity, ultra-low density and highly crossbound three dimensional webs, and consists of silica [37][38].…”

“…Research on silica aerogel, which has lower heat conduction [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] when compared to other materials produced through complicated and expensive procedures [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41], has proved that it has higher potential for thermal and acoustic insulation. Adding silica aerogel into construction materials can decrease their thermal conductivity or k-value significantly and result in thermal performance which was not previously possible [5].…”