A review on the buffering capacity of earth building materials

McGregor, Fionn; Heath, Andrew; Maskell, Daniel; Fabbri, Antonin; Morel, Jean‐Claude

doi:10.1680/jcoma.15.00035

Cited by 73 publications

(58 citation statements)

References 29 publications

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“…These effects create a contradiction, since the sustainability (Melià et al 2014;Arrigoni et al 2017a, b) and positive effect on indoor air quality (McGregor et al 2016) associated with houses built of earth are the competitive advantage compared to conventional materials in face of climate change. To address this contradiction researchers have been investigating alternative methods of stabilization both with traditionally used vernacular materials and with contemporary, mainly synthetic materials.…”

Section: The Contradiction Of Cement Stabilizationmentioning

confidence: 99%

Durability of Stabilized Earthen Constructions: A Review

Medvey

Dobszay

2020

Geotech Geol Eng

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It has become general practice to stabilize earthen materials with chemical binders, since one of their main weaknesses is their lack of durability. The most commonly used stabilizer is cement, which reinforces earth by enhancing its strength and water resistance with chemical bonds, while at the same time significantly increases its embodied energy and reduces its sorption capacity. These side-effects greatly reduce the sustainability appeal of earthen materials, leading to a contradiction in this application of cement. Since the researcher community has been aware of this more and more results are published of experiments with alternative stabilizers. This review provides an overview of research about the durability of stabilized earthen walls, the methods used to assess it and parameters that have been shown to affect it. The review features a brief history of this field, but focuses more on recently published data about the water erosion performance of stabilized earthen construction materials. Conclusions about the existing test methods are drawn, with directions for further development suggested.

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Section: The Contradiction Of Cement Stabilizationmentioning

confidence: 99%

Durability of Stabilized Earthen Constructions: A Review

Medvey

Dobszay

2020

Geotech Geol Eng

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“…The CEBs were prepared with Kaolinite clay, therefore having poor sorption characteristics compared to other clays [34]. The clay minerals in the earth plasters was not determined but the results indicate the presence of clay with strong sorption capacities, especially when considering that the clay sized particle content in the plaster is very low (plaster has a clay and silt sized fraction of 10% whereas the CEB has a clay content of 25%).…”

Section: Moisture Bufferingmentioning

confidence: 99%

The influence of two crop by-products on the hygrothermal properties of earth plasters

Palumbo

McGregor

Heath

et al. 2016

Building and Environment

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a b s t r a c tThe incorporation of natural fibres in earth construction elements is a common practice that is found both in traditional and in contemporary building systems. The positive effect that such materials have on the mechanical properties of the clay mixtures has been established in previous research. However, their effect on the hydric and thermal properties is less well understood and these properties are important for thermal mass and passive humidity control in buildings, aspects linked to occupant health and reductions in energy use. The present paper includes the first in-depth study of the thermal conductivity and diffusivity, as well as the water vapour permeability and moisture buffering of compressed earth blocks and plasters incorporating natural fibres. Two different vegetable materials, barley straw and corn pith, were mixed to the clay materials in two different percentages (1% and 2%). The results show that the vegetable materials have a great impact on the thermal properties and the apparent density of the mixtures, but a limited effect on the hydric properties. The greatest improvement of the moisture behaviour was shown by the specimens incorporating 2% of corn pith. This improvement is greater for short time exposure than long time exposure. After 3 h, these mixtures adsorbed 15.5 g of moisture more than the plain samples, but after 8 h the difference was reduced to 8.0 g. This indicates that such mixtures might be more appropriate in environments with short and intense moisture loads, such as bathrooms. Previous research has demonstrated that earth provides the highest moisture buffering capacity of common building materials, and this research demonstrates how these properties can be enhanced for specific applications.

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“…While the good hygrothermal performance of raw earth used in buildings is well understood and acknowledged, less is known about the performance of modern RE buildings and in particular on the influence that stabilisers may have on their hygroscopic properties [17]. 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].…”

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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A review on the buffering capacity of earth building materials

Cited by 73 publications

References 29 publications

Durability of Stabilized Earthen Constructions: A Review

Durability of Stabilized Earthen Constructions: A Review

The influence of two crop by-products on the hygrothermal properties of earth plasters

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

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