Eco-Efficient Earthen Plasters: The Influence of the Addition of Natural Fibers

Lima, José Pinto de; Faria, Paulina

doi:10.1007/978-94-017-7515-1_24

Cited by 39 publications

(55 citation statements)

References 8 publications

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“…Similar comparison can be made with the results obtained by Faria et al [14], which assessed a ready-mixed earth-based mortar with addition of oat straw fibers (shrinkage less than 1%), and Lima & Faria [15] which characterized six mortar specifically formulated with different additions of oat straw fibers and typha fiber wool (shrinkage also less than 1%). The mortars of both of these studies were prepared with proportions of clayish earth and siliceous sand similar to the mortars assessed in the present study.…”

Section: Fig 8 -Thermal Conductivitysupporting

confidence: 79%

“…This lead the researchers to test a modification of the protocol procedure, which mainly consist in previously wetting the support surface with a suspension (liquid mixture) of the clayish earth and water. This protocol modification clearly improved the [15], that followed the same DIN 18947 [11] test procedures, it may be also possible to establish some comparison with the results obtained by Maddison et al [5]. The first two mentioned studies also obtained a very high water vapor adsorption and desorption, both surpassing the adsorption values defined in the highest adsorption class (WS-III) of the DIN 18947 [11] (≥ 60.0 g/m 2 of adsorbed water vapor after 12h at temperature of 23ºC and a RH of 80%).…”

Section: Fig 8 -Thermal Conductivitymentioning

confidence: 90%

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Earthen Plasters Based on Illitic Soils from Barrocal Region of Algarve: Contributions for Building Performance and Sustainability

Lima

Faria

Silva

2016

KEM

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Abstract. Clayish earth-based mortars can be considered eco-efficient products for indoor plastering since they can contribute to improve important aspects of building performance and sustainability. Apart from being products with low embodied energy when compared to other types of mortars used for interior plastering, mainly due to the use raw clay as natural binder, earth-based plasters may give a significant contribution for health and comfort of inhabitants. Due to high hygroscopicity of clay minerals, earth-based mortars present a high adsorption and desorption capacity, particularly when compared to other type of mortars for interior plastering. This capacity allows earth-based plasters to act as a moisture buffer, balancing the relative humidity of the indoor environment and, simultaneously, acting as a passive removal material, improving air quality. Therefore, earth-based plasters may also passively promote the energy efficiency of buildings, since they may contribute to decreasing the needs of mechanical ventilation and air conditioning. This study is part of an ongoing research regarding earth-based plasters and focuses on mortars specifically formulated with soils extracted from Portuguese 'Barrocal' region, in Algarve sedimentary basin. This region presents high potential for interior plastering due to regional geomorphology, that promote the occurrence of illitic soils characterized by a high adsorption capacity and low expansibility. More specifically, this study aims to assess how clayish earth and sand ratio of mortars formulation can influence the physical and mechanical properties of plasters. For this assessment four mortars were formulated with different volumetric proportions of clayish earth and siliceous sand. The results from the physical and mechanical characterization confirmed the significantly low linear shrinkage of all the four mortars, as well as their extraordinary adsorption-desorption capacity. These results presented a positive correlation with mortars´ clayish earth content and are consistent with the mineralogical analysis, that confirmed illite as the prevalent clay mineral in the clayish earth used for this study. Regarding mechanical resistance, although the promising results of the adhesion test, the flexural and compressive strength results suggest that the mechanical resistance of these mortars should be slightly improved. Considering the present results the mortars mechanical resistance improvement may be achieved through the formulation of mortars with higher clayish earth content, or alternatively, through the addition of natural fibers to mortars formulation, very common in this type of mortars. Both those options will be investigated in future research.

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Section: Fig 8 -Thermal Conductivitysupporting

confidence: 79%

Section: Fig 8 -Thermal Conductivitymentioning

confidence: 90%

Earthen Plasters Based on Illitic Soils from Barrocal Region of Algarve: Contributions for Building Performance and Sustainability

Lima

Faria

Silva

2016

KEM

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“…Moisture absorption is 50 times higher for unbaked blocks than for bricks fired at high temperature [1]. However, only four references that focused on plasters studied this property on earth with plant aggregate or fiber, [17,25,30,31]. This sorption and desorption property can be considered as static or dynamic.…”

Section: Sorption-desorptionmentioning

confidence: 99%

Plant aggregates and fibers in earth construction materials: A review

Laborel-Préneron

Aubert

Magniont

et al. 2016

Construction and Building Materials

326

157

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Earth as a building material is increasingly being studied for its low environmental impact and its availability. Plant aggregates and fibers have been incorporated into the earth matrix in the aim of enhancing performance for thousands of years but scientific studies began quite recently. The present paper reviews the state of the art of research on the influence of these various natural and renewable resources in unfired earth materials such as compressed earth blocks, plasters, and extruded and stabilized blocks. This review, based on 50 major studies, includes characterization of the particles and treatments, and recapitulative tables of the material compositions, and the physical, mechanical, hygrothermal and durability performances of earth-based materials. A lack of references on hygroscopic and durability properties was observed. Future research orientations are thus suggested to promote and develop this type of sustainable material, which provides a solution for saving energy and natural resources. Highlights Earth-based products with plant aggregates as a sustainable material are reviewed.  Physicochemical and mechanical properties of plant aggregates or fibers are reviewed.  Mechanical, hygrothermal and durability performances of the composites are reviewed.  Further investigations are needed to promote these materials.

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“…The addition of fibres has been reported to influence the equilibrium moisture content and the dynamic moisture buffering properties but little information is available determining the extent of such influence, which is highly dependent on the kind of fibre added to the plaster. Lima and Faria [6] analysed six different clay mortars in which oat straw fibres or typha fibre wool had been added in different proportions. Their results indicate that the addition of fibres has little influence on the moisture adsorption and desorption of the plasters.…”

Section: Introductionmentioning

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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Eco-Efficient Earthen Plasters: The Influence of the Addition of Natural Fibers

Cited by 39 publications

References 8 publications

Earthen Plasters Based on Illitic Soils from Barrocal Region of Algarve: Contributions for Building Performance and Sustainability

Earthen Plasters Based on Illitic Soils from Barrocal Region of Algarve: Contributions for Building Performance and Sustainability

Plant aggregates and fibers in earth construction materials: A review

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

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