Durability of Thermal Renders with Lightweight and Thermal Insulating Aggregates: Regranulated Expanded Cork, Silica Aerogel and Expanded Polystyrene

Abstract

Following the trend of energy-efficient construction, renders with thermal insulation properties have been studied for replacing conventional renders. However, there are still few studies on the durability of these renders that may become a barrier for their implementation. In this study, the performance of lightweight renders for thermal insulation to accelerated aging cycles and freeze/thaw cycles is discussed. For this purpose, renders with regranulated expanded cork (GEC), silica aerogel (SA), and expanded polystyrene (EPS) were produced and tested for compressive strength, ultra-sound velocity, Young’s modulus, and thermal conductivity before and after accelerated aging cycles (hygrothermal, IR and freeze/thaw cycles). With this study, a comparison between the influence of different aggregates on renders is carried out in order to understand their effect on different properties of renders.

Research Development in Silica Aerogel Incorporated Cementitious Composites—A Review

“…Recent publications suggest also that the enhancement of the mechanical parameters with retained insulating properties might be achieved by adding other lightweight aggregates along with the aerogel [ 76 , 87 , 90 , 94 , 95 , 96 , 97 , 98 ]. Aggregates used in these solutions include expanded cork, expanded polystyrene, expanded glass or expanded perlite and vermiculite.…”

“…Aggregates used in these solutions include expanded cork, expanded polystyrene, expanded glass or expanded perlite and vermiculite. For example, Morgado et al used regranulated expanded cork, silica aerogel and expanded polystyrene as aggregates for energy-efficient building façades [ 87 ]. They indicated that, in doing so, the weight of the samples was decreased, whereas the compression strength was slightly increased.…”

“…From the results of the above-mentioned work, it can be inferred that the fire-resisting properties of silica aerogel might find application in the field of insulation materials. Such properties were investigated by several researchers [ 75 , 86 , 87 , 108 , 109 ]. In the publication of Ismail et al [ 86 ], for example, the investigators presented an experimental study on the energy efficiency of cement-based thermal cladding with silica aerogel amendment.…”

“…The researchers indicated that suitable energy efficiency and insulating capability were achieved [ 86 ]. Morgado et al [ 87 ], in turn, investigated the durability parameters of thermal renders with silica aerogel and other eco-friendly materials. The scope of the experiment was to expose samples to long-duration freeze/thaw cycles and to hygrothermal accelerated aging cycles.…”

Robust SiO2–Al2O3/Agarose Composite Aerogel Beads with Outstanding Thermal Insulation Based on Coal Gangue

“…Aerogels, miracle materials for the 21st century, are considered to be promising and useful because of their ultralow density (0.003–0.1 g/cm 3 ), high porosity (80–99.8%), low thermal conductivity (0.013–0.14 W/m·K), high specific surface area (500–1200 m 2 /g), low dielectric constant ( k = 1.0–2.0), and high acoustic impedance (~1.05 MRayl) [ 1 , 2 , 3 ]. Because of these excellent properties, aerogel materials have recently been the focus of considerable research and have been used in a wide range of applications such as thermal insulation [ 4 , 5 , 6 ], acoustic insulation [ 7 ], adsorption [ 8 , 9 ], flexible energy storage devices [ 10 ], and drug and catalyst carriers [ 11 ].…”