The moisture buffering capacity of unfired clay masonry

McGregor, Fionn; Heath, Andrew; Shea, Andrew; Lawrence, Michael B.

doi:10.1016/j.buildenv.2014.09.027

Cited by 145 publications

(85 citation statements)

References 19 publications

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“…The addition of alginate does not appear to drastically effect the sorption properties. This finding is in agreement with other studies which argue that the hygroscopic behaviour is linked primarily to the properties of the soil such as the particle size distribution and type of clay minerals present (McGregor et al, 2014b). Further investigation regarding the water vapour permeability and moisture buffering values would however be required before the humidity buffering behaviour could be fully characterised for the different clay-alginate combinations.…”

Section: Hygroscopic Sorption Propertiessupporting

confidence: 90%

“…Unfired earth can also offer further benefits such as improving indoor air quality and thermal comfort for inhabitants when exposed internally. For example, clay's hygroscopicity and excellent moisture buffering properties can help to maintain a healthy level of humidity within buildings, thereby reducing the risk of mould growth (Hall and Allinson, 2009;McGregor et al, 2014b). In addition, since unfired clay is a high density material, it also provides thermal mass within the building structure which acts as a passive form of heat storage as well as providing acoustic insulation (Morton, 2008).…”

Section: Biopolymers As Additives For Unfired Claymentioning

confidence: 99%

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Seaweed biopolymers as additives for unfired clay bricks

2016

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Unfired clay bricks are an environmentally friendly alternative to conventional masonry materials such as fired bricks and concrete blocks but their use is currently limited by their relatively poor mechanical and durability properties. While products like cement and lime are commonly added to earthen materials in an effort to improve their physical performance, these additives can also have a negative influence on the overall environmental impact. The purpose of this research is to investigate the use of alginate, a natural and renewable biopolymer obtained from brown seaweeds, as an admixture for unfired clay blocks. A total of 5 different alginates have been investigated and combined with 3 soil compositions to create prototype specimens which have then been characterised and compared in relation to flexural and compressive strength, microstructure, abrasive strength and hygroscopic behaviour. The results demonstrate that improvements in mechanical strength are dependent on the type of alginate used and the composition of the soil. The greatest increase in compressive strength is achieved using an alginate sourced from the Laminaria Hyperborea seaweed and offers a value more than double that of the equivalent control specimen. Increases in the alginate dosage do not necessarily lead to an increase in strength suggesting that there is an optimum concentration at which strength improvement is most effective.

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Section: Hygroscopic Sorption Propertiessupporting

confidence: 90%

Section: Biopolymers As Additives For Unfired Claymentioning

confidence: 99%

Seaweed biopolymers as additives for unfired clay bricks

2016

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“…A few studies have recently been published focusing on the humidity buffering potential of stabilised rammed earth (SRE) and compressed earth blocks, concluding that modern compressed earth can be a good moisture buffering material [18][19][20]. Other authors studied earthen plasters and advised the addition of aggregates in the mixture, such as natural fibres or synthetic gels, to enhance their hygroscopic properties [21,22].…”

Section: Introductionmentioning

confidence: 99%

Reduction of rammed earth's hygroscopic performance under stabilisation: an experimental investigation

Arrigoni

Grillet

Pelosato

et al. 2017

Building and Environment

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a b s t r a c tOne of the acknowledged qualities of rammed earth (RE) is its moisture buffering capacity. Recently, stabilisation of RE has become a common practice to improve the mechanical resistance but very little is known about the effect that stabilisation has on hygroscopic properties. The present study aims to fill this gap by understanding the role that stabilisation plays in the buffering and sorption capacity of RE. The use of alternative stabilisers such as fly ash and calcium carbide residue and a comparison with traditional unstabilised RE (URE) have also been investigated. Moreover, the effect of weathering, simulated by cyclic wetting-drying, on hygroscopic performance has been analysed. Moisture Buffer Value (MBV) testing, moisture and nitrogen adsorption-desorption isotherms and mercury intrusion porosimetry were performed on stabilised samples to examine microstructural phenomena responsible for behavioural changes. URE was confirmed to be a good-to-excellent passive air conditioner according to the MBV scale but its performance seemed to be highly influenced by the soil particle size distribution and mineralogy. Based on the experimental outcomes of the mixtures investigated, stabilisation had a detrimental effect on the moisture buffer capacity of rammed earth, likely due to the inhibition of the physico-chemical interactivity between moisture and clays. Weathering had a variable effect on the buffering capacity, depending on the availability of unreacted particles in the matrix.

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“…The practical Moisture Buffering Value (MBV practical ) was calculated using the maximum moisture uptake (g/m 2 ) after 8 hours of adsorption phase divided by the RH interval, which, in this case was 40%. We adopted similar procedure as in (McGregor et al 2014), where moisture buffering capacity of unfired clay masonry was studied.…”

Section: Moisture Buffer Valuementioning

confidence: 99%

Moisture Buffering Potential of Plasters for Energy Efficiency in Modern Buildings

Fořt

Doleželová

Černý

2017

Proccedings of 10th International Conference "Environmental Engineering"

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Abstract. Moisture level significantly affects durability of constructions, their thermal performance and quality of indoor air. Since building envelopes are subjected to a moisture gradient, additional ventilation systems are employed to maintain relative humidity on the desired level. Although modern advanced ventilation systems provide sufficient air exchange rate, their wider application is in conflict with sustainability development principles due to high energy demands. Moreover, according to the European legislation related to the Nearly Zero Energy Buildings (European Directives 2002/91/EC and 2010/31/EU), air tightness of building envelopes in order to provide high thermal resistance leads to large moisture loads in building interiors. Among other factors, a high level of relative humidity has negative effect on the work efficiency and health of building inhabitants. A detailed insight into building materials behavior during cyclic moisture loading was accessed within this study. The moisture buffering values of three interior plasters were investigated in order to describe influence of plasters on moderation of indoor environment. Particular materials were loaded according to the NORDTEST protocol by 8/16 h loading schema at 70/30% RH. Here, the excellent moisture buffer classification was obtained for lightweight perlite plaster (PT) with the highest total open porosity. However, contrary to the higher total open porosity of renovation plaster (PS), the core plaster (CP) achieved higher moisture buffer capacity than PS. This discrepancy refers to the influence of the pore size distribution which is, besides the total open porosity, essential for a detailed characterization of moisture buffering potential of building materials. Based on the results of Mercury intrusion porosimetry, a correlation between pore size distribution and moisture buffer value was revealed.

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The moisture buffering capacity of unfired clay masonry

Cited by 145 publications

References 19 publications

Seaweed biopolymers as additives for unfired clay bricks

Seaweed biopolymers as additives for unfired clay bricks

Reduction of rammed earth's hygroscopic performance under stabilisation: an experimental investigation

Moisture Buffering Potential of Plasters for Energy Efficiency in Modern Buildings

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