Assessing the performance of earth building materials: a review of recent developments

Fabbri, Antonin; Morel, Jean‐Claude; Gallipoli, Domenico

doi:10.21809/rilemtechlett.2018.71

Cited by 41 publications

(29 citation statements)

References 73 publications

(100 reference statements)

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“…Liquid water permeability is defined as the product between the intrinsic permeability and the relative permeability coefficient [27]. This can be measured with an oedometer using the variable hydraulic load method, as described by the French Standard NF X 30-442 [28].…”

Section: Hygrothermal Properties Of Earth−based Materials and Methodomentioning

confidence: 99%

“…Finally, the hygroscopic buffering potential of earth materials can be assessed through the determination of maximal absorption value and moisture buffering value (MBV). The maximal absorption value is defined in [27] as a measurement of earth sample mass, initially stabilised at 50% RH, after 12 h at a relative humidity of 80%. The MBV method consists of measures of mass variation caused by moistening cycles, per unit of surface, and was defined for the first time in the NORDTEST project [31].…”

Section: Hygrothermal Properties Of Earth−based Materials and Methodomentioning

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: Hygrothermal Properties Of Earth−based Materials and Methodomentioning

confidence: 99%

Hygrothermal Properties of Raw Earth Materials: A Literature Review

2019

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“…Raw earth has fascinating thermo-hygro-mechanical qualities that can help reduce the environmental effect of buildings not only during construction but also during their lifetime. Nonetheless, one of the barriers to the widespread use of raw earth in construction is that [6,7].…”

Section: Introductionmentioning

confidence: 99%

“…However, because of the world heritage of earthen construction traditions, there are many construction techniques with an infinite number of variants adapted to the quality of the earth and the level of development of know-how, reflecting the identity of the places and cultures. The CRATerre group [7] created a diagram with twelve techniques for using soil for construction. Eight techniques are used daily and constitute the main techniques: adobe, pisa, earth-straw, cob, shaped earth, extruded earth, compressed earth blocks Guillaud and Houben (1995) have schematically listed the twelve main techniques in a "wheel" of earthen construction techniques.…”

mentioning

confidence: 99%

Towards a Sustainable Building Material in Hot Arid Environments: Compressed and Stabilized Earth Brick (CSEB) Prototype

Laouni¹,

Mazouz²

2021

IJSDP

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The aim of this research is to develop a material that will improve indoor comfort by eliminating the effect of hot walls during the summer and lowering the amount of energy consumed by air conditioning. It also aims to promote enough thermal autonomy to maintain thermal comfort in hot arid areas, such as Biskra's climate in southeastern Algeria, as well as to provide designers with a healthy, durable, and long-lasting material, solid, and low-cost material option. The thermal properties of this material, including the proposed combination and manufacturing procedure for these compressed and stabilized earth bricks, will be demonstrated. The study's prototype will be described.

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“…A state-ofthe-art on the hygrothermal properties of numerous earth may be found in [1]. Also, it is widely acknowledged that the heterogeneity of structure of this material may lead to large experimental uncertainties, and current standards are not adapted for this material [2].…”

Section: Introductionmentioning

confidence: 99%

Uncertainty and sensitivity analysis applied to a rammed earth wall: evaluation of the discrepancies between experimental and numerical data

et al. 2020

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Due to the environmental impact of building materials, researches on sustainable materials, such as bio-based and earth materials, are now widespread. These materials offer numerous qualities such as their availability, recyclability and their ability to dampen the indoor relative humidity variations due to their hygroscopicity. As these materials can absorb large amount of humidity, numerical and experimental studies of their hygrothermal behaviour are crucial to assess their durability. To validate a hygrothermal model, numerical and experimental data have to be confronted. Such confrontation must take into consideration the uncertainties related to the experimental protocol, but also to the model. Statistical tools such as uncertainty and global sensitivity analysis are essential for this task. The uncertainty analysis estimates the robustness of the model, while the global sensitivity analysis identifies the most influential input(s) responsible for this robustness. However, these methods are not commonly used because of the complexity of hygrothermal models, and therefore the prohibitive simulation cost. This study presents a methodology for comparing the numerical and experimental data of a rammed earth wall subjected to varying temperature and relative humidity conditions. The main objectives are the investigation of the uncertainties impact, the estimation of the model robustness, and finally the identification of the input(s) responsible for the discrepancies between numerical and experimental data. To do so, a recent and low-cost global variance-based sensitivity method, named RBD-FAST, is applied. First, the uncertainty propagation through the model is calculated, then the sensitivity indices are estimated. They represent the part of the output variability related to each input variability. The output of interest is the vapour pressure in the middle of the wall to confront it to the experimental measurement. Good agreement is obtained between the experimental and numerical results. It is also highlighted that the sorption isotherm is the main factor influencing the vapour pressure in the material.

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Assessing the performance of earth building materials: a review of recent developments

Cited by 41 publications

References 73 publications

Hygrothermal Properties of Raw Earth Materials: A Literature Review

Hygrothermal Properties of Raw Earth Materials: A Literature Review

Towards a Sustainable Building Material in Hot Arid Environments: Compressed and Stabilized Earth Brick (CSEB) Prototype

Uncertainty and sensitivity analysis applied to a rammed earth wall: evaluation of the discrepancies between experimental and numerical data

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