Hygrothermal behavior for a clay brick wall

Allam, Reda; Issaadi, Nabil; Belarbi, Rafik; Elmeligy, Mahmoud; Altahrany, Ayman

doi:10.1007/s00231-017-2271-5

Cited by 24 publications

(22 citation statements)

References 18 publications

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“…In order to test physical, mechanical and thermal characteristics sometimes the samples can be oven-dried at a temperature of 105 • , as for [14][15][16] or at 50 • C [17]. Moevus et al [14] point out that the determination of water content in earth is of paramount importance, as it affects the mechanical (decreasing the resistance [12]) and thermal properties of earth-based materials, so that many researches [16][17][18][19][20][21][22] pointed out the importance of determining the equilibrium soil moisture at ambient humidity and to compare it to relative humidity, environmental temperature, effects of soil grading, surface impermeability and activity of the clay (which is the affinity of clay to water, higher for swelling clays as montmorillonite).…”

Section: Hygrothermal Properties Of Earth−based Materials and Methodomentioning

confidence: 99%

“…When cement or gypsum content increase EMC decreases. Finally, Allam et al [21] find EMC values for clay bricks ranging from 3% to 7%. Indekeu et al [37] realize dynamic hygrothermal measurements of rammed earth material samples with a sorption isotherm, stabilizing at an uptaken volumetric moisture content ∆w = 9 kg m −3 .…”

Section: Sorption-desorption Isotherms For the Equilibrium Moisture Cmentioning

confidence: 99%

“…Medjelekh et al [19] use an analytic procedure to find vapour permeability as a function of the water content, with the higher value equal to 1.5 E−10 kg m −1 s −1 Pa −1 . Allam et al [21] find water vapour permeability for earth brick samples corresponding to 1.45 × 10 −10 kg m −1 s −1 Pa −1 up to 1.8 × 10 −10 kg m −1 s −1 Pa −1 .…”

Section: Water Vapour Permeability/water Vapour Resistance Factormentioning

confidence: 99%

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Hygrothermal Properties of Raw Earth Materials: A Literature Review

2019

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Raw earth historic and contemporary architectures are renowned for their good environmental properties of recyclability and low embodied energy along the production process. Earth massive walls are universally known to be able to regulate indoor thermal and hygroscopic conditions containing energy consumptions, creating comfortable interior spaces with a low carbon footprint. Therefore, earth buildings are de facto green buildings. As a result of this, some earthen technologies have been rediscovered and implemented to be adapted to the contemporary building production sector. Nevertheless, the diffusion of contemporary earthen architecture is decelerated by the lack of broadly accepted standards on its anti-seismic and thermal performance. Indeed, the former issue has been solved using high-tensile materials inside the walls or surface reinforcements on their sides to improve their flexural strength. The latter issue is related to the penalization of earth walls thermal behavior in current regulations, which tent to evaluate only the steady-state performance of building components, neglecting the benefit of heat storage and hygrothermal buffering effect provided by massive and porous envelopes as raw earth ones. In this paper, we show the results of a paper review concerning the hygrothermal performance of earthen materials for contemporary housing: great attention is given to the base materials which are used (inorganic soils, natural fibers, and mineral or recycled aggregates, chemical stabilizers), manufacturing procedures (when described), performed tests and final performances. Different earth techniques (adobe, cob, extruded bricks, rammed earth, compressed earth blocks, light earth) have been considered in order to highlight that earth material can act both as a conductive and insulating meterial depending on how it is implemented, adapting to several climate contests. The paper aims to summarize current progress in the improvement of thermal performance of raw earth traditional mixes, discuss the suitability of existing measurement protocols for hygroscopic and natural materials and provide guidance for further researches.

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Section: Hygrothermal Properties Of Earth−based Materials and Methodomentioning

confidence: 99%

Section: Sorption-desorption Isotherms For the Equilibrium Moisture Cmentioning

confidence: 99%

Section: Water Vapour Permeability/water Vapour Resistance Factormentioning

confidence: 99%

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Hygrothermal Properties of Raw Earth Materials: A Literature Review

2019

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“…Moreover, heat and moisture transfer equations were formulated in terms of temperature and relative humidity as transported variables. Allam et al [7] developed the model of the hygrothermal transfer in the clay brick which utilized the temperature and vapor partial pressure as driving potentials. Recently, the model of heat and moisture transfer in porous building materials which consisted of four equations, i.e., energy, liquid moisture, vapor and dry air balance equation, was presented in [8,9].…”

Section: Introductionmentioning

confidence: 99%

Investigation of the equilibrium and non–equilibrium models of heat and moisture transport in a wet porous building material

et al. 2019

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In the paper the equilibrium and non-equilibrium models of moisture transport across the wet building material are proposed and compared. The equilibrium condition between gaseous and liquid moisture phases in the first model is relaxed in the second one, where evaporation and condensation are driven by the difference between the actual moisture partial pressure and its saturation value. In both models moisture is assumed in the gaseous phase as well as continuous (funicular) and discontinuous (pendular) liquid phase. Moreover, the transport of moisture is tightly coupled with heat transfer, which is treated as the fully equilibrium process in both models. The proposed models are verified with numericalresults available in literature, namely with temporal variation of temperature in selected location in the building material. Additionally, predicted with both models temporal changes of the moisture content in three selected points and the total moisture content are compared. Both models produced similar results.

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“…The transport equations were expressed in terms of two parameters, namely the temperature of the medium and relative humidity. A model of the moisture transfer in the clay brick was developed Allam et al [10]. This model was based on the same driving potentials used in [9].The extended model of moisture and heat transfer in homogeneous porous building materials was presented in [11,12].…”

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confidence: 99%

Analysis of Non-Equilibrium and Equilibrium Models of Heat and Moisture Transfer in a Wet Porous Building Material

et al. 2020

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In the proposed paper, non-equilibrium and equilibrium models of heat and moisture transfer through wet building materials are presented and compared. In the former, the mass transfer between liquid and gaseous moisture results from the difference between the partial pressure of water vapor and its saturation value. In the second model, the equilibrium between both phases is assumed. In the non-equilibrium model, liquid moisture can be in the continuous (funicular) or discontinuous (pendular) form. The transfer of moisture for each proposed model is tightly coupled with the energy transfer, which is assumed to be an equilibrium process. The time step and grid size sensitivity analysis of both numerical models are performed primarily. The verification of the model is based also on the numerical data available in literature. Finally, obtained with considered models, temporal variations of moisture content in three locations in the computational domain are compared. Reasonable conformity of results is reported, and discrepancies related to differences in formulations of models are discussed.

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Hygrothermal behavior for a clay brick wall

Cited by 24 publications

References 18 publications

Hygrothermal Properties of Raw Earth Materials: A Literature Review

Hygrothermal Properties of Raw Earth Materials: A Literature Review

Investigation of the equilibrium and non–equilibrium models of heat and moisture transport in a wet porous building material

Analysis of Non-Equilibrium and Equilibrium Models of Heat and Moisture Transfer in a Wet Porous Building Material

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