In-Situ Tests on Silica Aerogel-Based Rendering Walls

Flores‐Colen, Inês; Pedroso, Marco; Soares, António O.; Gomes, M. Glória; Ramos, Nuno M. M.; Maia, Joana; Sousa, Rui A.; Sousa, Hipólito; Silva, Luís

doi:10.23967/dbmc.2020.190

Cited by 4 publications

(7 citation statements)

References 11 publications

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Section: Resultsmentioning

confidence: 99%

“…Despite the low adhesive strength, which is expected in these types of thermal mortars, cohesive fractures in the render itself were observed, which were within the admitted values in ETAG 004 [64] (for a thermal multilayered system with boards insulating materials) and the results obtained by Maia et al [66] for thermal rendering systems. As discussed by Flores-Colen et al [67], because of the low weight of aerogel cement-based renders and their vulnerability to thermal variation, the low adhesive strength could be admitted. In terms of impact resistance, higher cracking of the coating and dent diameter after the EN and ETAG aging methods were observed (see Figure 8), where the water action contributed to increasing the deterioration; however, these values should be carefully analyzed since the measurement procedure (in millimeters) presented some variation.…”

Section: Methodsmentioning

confidence: 99%

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

et al. 2021

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The widespread application of innovative thermal enhanced façade solutions requires an adequate durability evaluation. The present work intends to assess the durability of a new aerogel cement-based rendering system through the adaptation of different accelerated aging cycles, such as heating–freezing, freeze–thawing, and heat–cold. Several mechanical properties and also capillary and liquid water absorptions were tested for uncoated and coated specimens. A decrease in the mechanical strength, especially after freeze–thaw cycles, was observed. However, the water action promoted the late hydration of the cement paste contributing to the densification of the matrix and, consequently, the increase of the adhesive strength. Additionally, a decrease in the dynamic modulus of elasticity and an increase in the Poisson’s ratio were observed after aging, which indicates a higher capacity of the render to adapt to substrate movements, contributing to a reduction of cracking.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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

et al. 2021

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“…In another study, Sakiyama et al [4] exposed large-scale wall prototypes of trial mixtures of ACM to severe weathering cycles in the laboratory at which the walls insulated by ACM showed signs of excessive water intrusion after the weathering cycles. In [9][10][11][12][13][14][15], the Acap of trial mixtures of ACMs was declared in based a single round of measurement, i.e., one wetting and drying cycle, as specified in EN ISO 1015-18 [16]. The declared values in [9][10][11][12][13][14][15] ranged from 0.48 and 2.8 kg/(m 2 •min 0.5 ), which are all higher than the stated requirement for thermal insulation coating mortars of less than 0.4 kg/(m 2 •min 0.5 ) [17].…”

Section: Introductionmentioning

confidence: 99%

“…In [9][10][11][12][13][14][15], the Acap of trial mixtures of ACMs was declared in based a single round of measurement, i.e., one wetting and drying cycle, as specified in EN ISO 1015-18 [16]. The declared values in [9][10][11][12][13][14][15] ranged from 0.48 and 2.8 kg/(m 2 •min 0.5 ), which are all higher than the stated requirement for thermal insulation coating mortars of less than 0.4 kg/(m 2 •min 0.5 ) [17]. The literature review highlights that studies on the Acap of ACMs are limited to a few studies that focus on trial mixtures with scattered results.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on the capillary water absorptivity of an aerogel-based coating mortar under subsequent drying and wetting cycles

Karim,

Kalagasidis,

Johansson

2023

J. Phys.: Conf. Ser.

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Aerogel-based coating mortars with thermal conductivities ranging from 30 to 50 mW/(m·K) are an emerging type of thermal insulation coating mortar. They are intended for retrofitting uninsulated building envelopes due to their thermal performance which is comparable to conventional thermal insulation materials such as mineral wool. Meanwhile, their long-term hygrothermal performance and the reliability of the material properties are not fully demonstrated since these normally are declared based on single-cycle laboratory measurements. This paper presents laboratory measurements to determine the capillary water absorptivity of a commercial aerogel-based coating mortar after three consecutive wetting and drying cycles. The effect of the chosen drying (elevated versus room temperature) and sealing condition (sealed versus unsealed samples) on the measurement results were also assessed. The results show that the capillary water absorptivity of the samples increased after each repeated wetting and drying cycle regardless of the drying and sealing conditions. After three cycles, the measured capillary water absorption was more than five times higher than the initial measurement. Future research should investigate the causes of the observation and whether it applies to other aerogel-based coating mortars.

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“…Among the studies on ACMs, [ 17 , 18 , 19 , 20 , 21 , 22 , 23 ] reported results on A cap for different trial mixtures of ACMs. Here, pre-conditioned samples were measured only once, and their properties were declared after the first wetting cycle.…”

Section: Introductionmentioning

confidence: 99%

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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In-Situ Tests on Silica Aerogel-Based Rendering Walls

Cited by 4 publications

References 11 publications

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

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

Experimental study on the capillary water absorptivity of an aerogel-based coating mortar under subsequent drying and wetting cycles

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

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