Durability of a New Thermal Aerogel-Based Rendering System under Distinct Accelerated Aging Conditions

Maia, Joana; Pedroso, Marco; Ramos, Nuno M. M.; Flores‐Colen, Inês; Pereira, Pedro F.; Silva, Luís

doi:10.3390/ma14185413

Cited by 16 publications

(17 citation statements)

References 52 publications

(61 reference statements)

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“…A study by Ibrahim et al revealed that the application of an additional insulation layer in the form of a silica aerogel-based render on an uninsulated building or on a building with existing interior insulation results in a reduction in or complete removal of the moisture problem [ 111 ]. Moreover, Maia et al demonstrated that the application of an additional protective layer to aerogel reduces the negative effects of accelerated aging and results in increased durability of the mortars over a longer service life [ 113 ].…”

Section: Durability and Performance Of Silica Aerogel-based Cementiti...mentioning

confidence: 99%

Research Development in Silica Aerogel Incorporated Cementitious Composites—A Review

2022

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This paper presents an analysis of research results for silica aerogel cement composites over the past twenty years. Recently, two trends in the development of these composites have been noted, towards structural applications and towards ultralight composites for coatings and renders. Ongoing research shows that important aspects of cementitious composites with good mechanical performance are the proper selection of aggregates and improved adhesion at the silica aerogel–cement binder interface, which will guarantee high compressive strength with the lowest possible thermal conductivity. The best physicomechanical performance of aerogel cement composites with low thermal conductivity below 0.03 W/(m·K) was obtained when cenospheres and aerogel were used in a weight percentage of 5%. In turn, the prerequisites for using aerogel cement composites as coatings for energy-efficient building façades are the use of large amounts of silica aerogel as a substitute for lightweight aggregates or the selection of an optimal composition of lightweight aggregates and aerogel, ensuring the lowest possible thermal conductivity coefficient. Other important standpoints are water transport and moisture protection of the silica aerogel-based coatings. Therefore, in recent years, more and more elements of the hygrothermal performance, porosity and durability of silica aerogel cement composites have been developed. The article also points out the weaknesses of the application of silica aerogel in the cement matrix, the most important of which are the lack of adhesion at the boundary of the aerogel–cement binder, the increased porosity of the composite, the high water absorption capacity and the significant decrease in compressive strength with large volumes of silica aerogel. Solving these issues will certainly contribute to the wider applicability of these materials in the construction industry.

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Section: Durability and Performance Of Silica Aerogel-based Cementiti...mentioning

confidence: 99%

Research Development in Silica Aerogel Incorporated Cementitious Composites—A Review

2022

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“…Building components differential movements and the lack of capacity of the render to follow the deformation of the substrate, could lead to tensions and cracking. The combined action of temperature and water highly contribute to the degradation of renders [33]. The freeze-thawing of water retained in the pores could lead to cracking.…”

Section: Climate-induced Degradation Of Rendered Façades: Degradation...mentioning

confidence: 99%

Impact of climate change on the degradation of rendered façades: Expectations for a dry and hot summer temperate climate

Barrelas

Silva²,

Brito³

et al. 2022

IOP Conf. Ser.: Earth Environ. Sci.

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Climate change is accelerating and can seriously affect the built environment, if not properly acknowledged in the design and maintenance stages. Despite the globally expected warming, climate changes will differ depending on region and climate type. What implications will temperature, precipitation and wind changes have on the degradation of the building envelope, in Southern Europe? How will the performance of façade claddings be affected by the end of the century? The purpose of this research is to determine the expected impact of climate change on the degradation of rendered façades, in a dry and hot summer temperate climate. This study is based on the complex relationship between climate parameters projections for Portugal and the known effects of environmental agents on the degradation of renderings. Projections indicate the increase of mean temperature and heat waves, reduction of precipitation and wet days, intensification of rainfall in shorter periods and decrease of wind speed in most of the country. Notwithstanding the projections’ inherent uncertainty, more cracking and fewer stains are expected. Due to the cracking increase, more loss of adhesion is probable. Further research is necessary to assess the risks of intense rainfall events to rendered façades, considering the also projected precipitation decrease.

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“…Furthermore, the declared material properties of these ACMs are, like for other building materials, based on laboratory measurements and analyzed under controlled climatic conditions. Likewise, and apart from a number of studies in the laboratory [ 5 , 6 , 7 ], the correlation between the declared moisture properties of ACMs and their long-term performance when exposed to real climate loads in the field is not yet confirmed. This could partly be because the material is relatively new but also due to the fact that moisture safe design is practiced mainly in regions with high moisture loads on buildings [ 8 , 9 , 10 , 11 , 12 , 13 ].…”

Section: Introductionmentioning

confidence: 97%

“…The range of measured A cap was 0.48–2.8 kg/m 2 ·min 0.5 , which is higher than the stated requirement (less than 0.4 kg/m 2 ·min 0.5 ) in EN ISO 998-1. Furthermore, in [ 5 , 6 , 7 , 24 , 25 , 26 ], the long-term performance of trial mixtures of ACMs was studied using artificial weathering cycles in the laboratory. Trial mixtures of ACMs were produced in the laboratory by mixing aerogel granules to a mortar mixture.…”

Section: Introductionmentioning

confidence: 99%

“…Trial mixtures of ACMs were produced in the laboratory by mixing aerogel granules to a mortar mixture. While the majority of these studies focused on thermal performance, [ 6 , 7 ] also studied the water absorptivity of trial mixtures of ACMs. Maia et al [ 7 ] evaluated the A cap of ACM samples before and after they were exposed to various consecutive weathering cycles (wetting-drying, heating-freezing combined with infrared radiation) in the laboratory.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Karim

Johansson

Kalagasidis

2022

Gels

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Aerogel-based coating mortars are energy-efficient composites with thermal conductivities of 30–50 mW/(m·K). They are useful when retrofitting uninsulated building envelopes, particularly in listed masonry buildings, as shown in studies. Meanwhile, the long-term reliability of their hygrothermal properties, typically declared after a single laboratory measurement, is not confirmed. To illustrate the latter and by combining experimental and numerical methods, this study shows that (1) the capillary water absorptivity of a commercially available aerogel-based coating mortar increases after repeated drying and wetting cycles, and (2) leads to a higher moisture content in a masonry wall. After the third cycle, the measured water absorption was more than five times higher than after the first one. Based on numerical simulations, the increasing capillary water absorptivity results in 36% higher relative humidity in the wall if the aerogel-based coating mortar is applied externally and exposed to driving rain. Future research should investigate the reasons behind the observed deviations in the capillary water absorptivity and whether it applies to other types of aerogel-based coating mortars.

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Durability of a New Thermal Aerogel-Based Rendering System under Distinct Accelerated Aging Conditions

Cited by 16 publications

References 52 publications

Research Development in Silica Aerogel Incorporated Cementitious Composites—A Review

Research Development in Silica Aerogel Incorporated Cementitious Composites—A Review

Impact of climate change on the degradation of rendered façades: Expectations for a dry and hot summer temperate climate

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

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