13 results on '"Clayish earth"'
Search Results
2. Characterization of earthen plasters – Influence of formulation and experimental methods
- Author
-
Tânia Santos and Paulina Faria
- Subjects
clayish earth ,phase change material ,sand ,Architecture ,NA1-9428 - Abstract
All over the world there is a vast heritage of earth construction where earth plasters were applied. Nowadays, due to environmental but also technical reasons, new earth plasters are also applied on common new masonries. That is why its characterization, in the laboratory but also in situ, is very important. In the present study, a pre-mixed earth plastering mortar (as control) and nine earth-based plastering mortars formulated in laboratory with different compositions were characterized. These mortars were formulated with 1:3 (illitic clayish earth:aggregate) volumetric ratio. The aggregate comprises a variation of fine and coarse sand and the partial replacement of the fine sand by a phase change material (PCM). The influence of the addition of a low amount of oat fibers is also evaluated. The mortars were characterized by different methods in laboratory and on an experimental wall exposed outdoors by destructive and nondestructive methods: dry bulk density, dynamic modulus of elasticity, flexural and compressive strengths, adhesive and shear strengths, dry abrasion resistance, surface cohesion, ultrasonic pulse velocity and hardness. Results were discussed and some were correlated. Most mortars present good mechanical strengths. However, the addition of PCM significantly decrease the mechanical strength of mortars. In terms of mechanical properties, the addition of oat fibers only promotes an improvement on adhesive strength. The simple surface hardness by durometer present laboratory and in situ results well correlated for earth mortars without PCM.
- Published
- 2020
3. Avaliação do envelhecimento natural e de tratamentos superficiais ecológicos em rebocos de terra.
- Author
-
SANTOS, TÂNIA, GOMES, RICARDO, and FARIA, PAULINA
- Subjects
SURFACE preparation ,CONCRETE masonry ,CONCRETE blocks ,NONDESTRUCTIVE testing ,SURFACE of the earth ,LINSEED oil - Abstract
Copyright of Conservar Património is the property of Associacao Profissional de Conservadores-Restauradores de Portugal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2020
- Full Text
- View/download PDF
4. Earth Plasters: The Influence of Clay Mineralogy in the Plasters' Properties.
- Author
-
Lima, José, Faria, Paulina, and Santos Silva, António
- Subjects
MINERALOGY ,PLASTER ,CLAY ,MODERN architecture ,CLAY minerals ,VERNACULAR architecture ,ACID dyeing (Textiles) - Abstract
Earth-based mortars have been used all over the world since ancient times in an extensive range of building types from vernacular architecture to monuments. Plastering is one of the most common contemporary applications of earth-based mortars used for earthen-building conservation or modern architecture. Raw earth is a very diverse natural material, and clay minerals play a key role in plaster properties being responsible for their setting process and providing the capacity of balancing the indoor hygrometric conditions of buildings. This capacity offers significant benefits to energy savings delivering comfort and health of inhabitants and also contributes to building conservation. For this study, three mortars were produced with different clayish earths to assess the influence of clay mineralogy. Mortars characterization confirmed that clay mineralogy drives important plaster properties, such as vapour adsorption and drying shrinkage, while also having a significant influence on mechanical strength, dry abrasion, and thermal conductivity. Within the studied mortars, illitic clayish earth stands outs as more adequate for earth-based plasters, showing balanced properties, namely linear drying shrinkage, mechanical strength, dry abrasion, and water vapour adsorption. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
5. Earth-based mortars for repair and protection of rammed earth walls. Stabilization with mineral binders and fibers.
- Author
-
Gomes, Maria Idália, Faria, Paulina, and Gonçalves, Teresa Diaz
- Subjects
- *
PISE , *MORTAR , *BINDING agents , *CONSTRUCTION materials , *SUSTAINABILITY - Abstract
The use of earth as a building material offers many advantages in terms of sustainability: it is a natural material, most probably non-toxic and ecological, with low energy intensity, low carbon emissions and recyclable. Earth-based mortars are re-gaining its place as building materials for plastering, rendering and repair of earthen walls, not only in the sustainable context but also in terms of efficiency. However, the scientific knowledge about these mortars is still scarce. In particular, the opinions regarding the effects of adding fibers or mineral binders as stabilizers, to improve the performance of the mortar, are contradictory. The study presented in this article is intended to advance the knowledge about the effects of adding low amounts of hemp fibers, hydrated air lime, hydraulic lime, natural cement and Portland cement on the mechanical (flexural and compressive strength, dynamic modulus of elasticity), physical (shrinkage, thermal conductivity, porosity) and hydric (water absorption under low pressure, capillary water absorption, drying) characteristics of mortars formulated with different earth materials. Results show that the addition of the fibers decreases the thermal conductivity of the mortars, which is remarkably good for the mortars made from clayey soil, and slowers the drying of the mortars. They also show that adding the mineral binders will negatively affect the hydric behaviour of the mortars: the water absorption coefficient increases and the drying become slower as the percentage of binder increases. In addition, the use of these binders has no significant effect on the flexural and compressive strength of the mortar. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
6. Earth Plasters: The Influence of Clay Mineralogy in the Plasters’ Properties
- Author
-
Paulina Faria, José Tarcísio Lima, António Santos Silva, and DEC - Departamento de Engenharia Civil
- Subjects
Water erosion ,Visual Arts and Performing Arts ,Range (biology) ,hygroscopicity ,mortar characterization ,0211 other engineering and technologies ,Geochemistry ,020101 civil engineering ,02 engineering and technology ,Conservation ,illitic clay ,montmorillonitic clay ,0201 civil engineering ,vapour adsorption ,pore size distribution ,021105 building & construction ,Architecture ,Vernacular architecture ,drying shrinkage ,clayish earth ,kaolinitic clay ,water erosion ,Mortar ,Clay minerals ,Earth (classical element) ,Geology - Abstract
Earth-based mortars have been used all over the world since ancient times in an extensive range of building types from vernacular architecture to monuments. Plastering is one of the most common contemporary applications of earth-based mortars used for earthen-building conservation or modern architecture. Raw earth is a very diverse natural material, and clay minerals play a key role in plaster properties being responsible for their setting process and providing the capacity of balancing the indoor hygrometric conditions of buildings. This capacity offers significant benefits to energy savings delivering comfort and health of inhabitants and also contributes to building conservation. For this study, three mortars were produced with different clayish earths to assess the influence of clay mineralogy. Mortars characterization confirmed that clay mineralogy drives important plaster properties, such as vapour adsorption and drying shrinkage, while also having a significant influence on mechanical strength, dry abrasion, and thermal conductivity. Within the studied mortars, illitic clayish earth stands outs as more adequate for earth-based plasters, showing balanced properties, namely linear drying shrinkage, mechanical strength, dry abrasion, and water vapour adsorption. authorsversion inpress
- Published
- 2020
7. Can an earth plaster be efficient when applied on different masonries?
- Author
-
Paulina Faria, Tânia Santos, Vitor Silva, and DEC - Departamento de Engenharia Civil
- Subjects
Materials science ,Absorption of water ,0211 other engineering and technologies ,02 engineering and technology ,Durability ,In situ test ,021105 building & construction ,Architecture ,Geotechnical engineering ,021108 energy ,Masonry ,Safety, Risk, Reliability and Quality ,Civil and Structural Engineering ,business.industry ,Building and Construction ,Clayish earth ,Strength of materials ,Mortar ,Oat straw ,Mechanics of Materials ,Plaster ,business - Abstract
PTDC/EPH-PAT/4684/2014. SAICT/23349/2016. Sem PDF conforme despacho. Earth mortars are known for being ecological but also reversible, contributing to comfort and aesthetic. Nevertheless, compatibility with different masonries is scarcely assessed. A commercial unstabilised ready-mixed earth mortar was produced with an ilitic earth with addition of sand and oat straw fibres. It was used to plaster different experimental masonry walls, at protected outdoors environmental conditions. The plasters applied on the masonries were visually monitored and characterized in situ by non-destructive techniques and in laboratory by bulk density and microstructure. The same mortar used for the plasters was characterized in laboratory in fresh state and, after drying, on prismatic specimens and specimens composed by a mortar layer applied on hollow bricks. Some variation of results occurs when the same unstabilised ready-mixed earth mortar is used to plaster different masonries, what may be related to the water absorption of the masonry materials. However, after six months the earth plaster presented durability on the different masonries when protected from rain. It proves that this ecological mortar is technically efficient to plaster different types of masonry, historical or contemporary. published
- Published
- 2019
8. Comparison of an earth mortar and common binder mortars for indoor plastering
- Author
-
José Lima, Paulina Faria, Rosário Veiga, and DEC - Departamento de Engenharia Civil
- Subjects
natural hydraulic lime ,SDG 7 - Affordable and Clean Energy ,air lime ,clayish earth ,gypsum ,plaster - Abstract
Plasters can be formulated with different binders, presenting different characteristics. Their main function is the protection of the substrate but, as indoor coatings, their influence on aesthetic performance and indoor air quality and comfort is also important. A plaster formulated with a clayish earth is compared to plasters formulated with common binders, namely hemihydrate gypsum, air lime and natural hydraulic lime. All the plasters have the same volumetric proportion binder:sand and were produced with the same siliceous washed sand. Results show that: the linear shrinkage of the earth mortar was the highest while the gypsum mortar presented no shrinkage; the bulk density of all the mortars were similar but there were differences on thermal conductivity, with advantages for the lime mortars, although this property is not significant for plasters application thicknesses; the gypsum mortar presented the highest mechanical properties while the lime mortars presented the lowest, even lower in comparison to the earth mortar; however, the resistance to dry abrasion was lower for the earth plaster; the earth plaster registers a very high hygroscopicity in comparison to all the other plasters, being an important contribution to indoor comfort, occupants health and energy consumption reduction. publishersversion published
- Published
- 2021
9. Assessment of natural aging and ecological surface treatments in earth renders
- Author
-
Tânia Santos, Ricardo Gomes, Paulina Faria, DEC - Departamento de Engenharia Civil, and CERIS - Polo NOVA
- Subjects
Durabilidade ,Museology ,Terra argilosa ,Conservation ,Natural exposure ,Clayish earth ,Durability ,Revestimento ,Mortar ,Coating ,Argamassa ,Caracterização in situ ,In situ characterisation ,Exposição natural - Abstract
PTDC/EPHPAT/4684/2014 SAICT/23349/2016 COMPETE 2020 [RESUMO] Em conservação, os rebocos de terra podem ser utilizados como camadas de sacrifício. No entanto, a terra é vulnerável quando em contacto com a água. A aplicação de tratamentos superficiais ecológicos em rebocos de terra pode aumentar a sua durabilidade, ecoeficiência e gama de aplicações. Neste artigo avaliou-se o comportamento de um reboco de argamassa pré-doseada de terra aplicado in situ sobre muretes experimentais de alvenarias de adobe e de blocos de betão (em exposição exterior com proteção), e em condições controladas de laboratório, sobre tijolo furado, após um período de quatro anos de envelhecimento. Foram aplicados diversos tratamentos superficiais sobre os rebocos: óleo de linhaça, mucilagem de aloé vera e água da cozedura de massa e de arroz. Os rebocos foram caracterizados de forma não destrutiva. O tratamento superficial com óleo de linhaça apresenta bons resultados e melhora a durabilidade do reboco, conferindo-lhe adequada protecção contra a degradação natural. [ABSTRACT] In conservation, earth renders can be used as sacrificial coatings. However, earth presents vulnerability when in contact with water. The application of ecological surface treatments on earth renders can be of great relevance, ensuring their durability while increasing eco-efficiency and extending its range of applications. The behaviour of a ready-mixed earth render applied in situ, on adobe and concrete block masonry experimental walls exposed outdoors with protection, and under controlled laboratory conditions, on hollow bricks, was evaluated after four years. Several superficial treatments were applied on the renders: linseed oil, mucilage of aloe vera and pasta and rice cooking water. The renders were characterized by non-destructive tests. The surface treatment with linseed oil presents good results and improves the durability of the earth render, giving it adequate protection against natural degradation. publishersversion published
- Published
- 2020
10. Earth-based plasters: the influence of clay mineralogy
- Author
-
José Lima, Paulina Faria, António Santos Silva, and DEC - Departamento de Engenharia Civil
- Subjects
Mortar ,Clayish Earth ,Kaolinitic Clay ,Ilithic Clay ,Shrinkage ,Montmorilonitic Clay ,Hygroscopicity - Abstract
Earth-based mortars have been used all over the world since ancient times, in an extensive range of building types, from vernacular architecture to monuments. Plastering is one of the most common current applications of earth-based mortars, as for earthen-building conservation or contemporary architecture. Raw earth is a very diverse natural raw material, and clay minerals play a key role on plaster properties, being responsible for its setting process and the capability of balancing the indoor hygrometric conditions of buildings, which have strong benefits on energy saving for comfort and health of inhabitants and building conservation. For this study three mortars were produced with different clayish earths to assess the influence of clay mineralogy. Mortars characterizations confirmed that clay mineralogy drives important plaster properties, like vapour adsorption, drying shrinkage, and also have significant influence on mechanical resistance, dry abrasion and thermal conductivity. Within the studied mortars illitic clayish earth stands outs as more adequate for earth-base plasters, with balanced linear drying shrinkage, mechanical resistance, dry abrasion and vapour adsorption. authorsversion published
- Published
- 2019
11. Argamassas de cal e terra: características e possibilidades de aplicação
- Author
-
Faria, Paulina, Naila Jamú, Inês Dias - Universidade NOVA de Lisboa, and projectos DB-Heritage (PTDC/EPH-PAT/4684/2014) financiado pela Fundação para a Ciências e a Tecnologia e PRESERVel, do LNEC
- Subjects
Alvenaria ,Repointing ,Refechamento de junta ,Cal aérea ,Terra argilosa ,Argamassa ,Reboco ,Refechamento de juntas ,Render ,Clayish earth ,Masonry ,Air lime - Abstract
Resumo Admite-se como hipótese que as argamassas mistas de cal e terra tenham resultado da prática profissional quando as condições económicas possibilitaram a adição de cais às argamassas vernáculas só de terra, que são susceptíveis à ação da água. Em estudos anteriores verificou-se que a adição de baixos teores de cal aérea a argamassas de terra de cor escura, embora tornem as argamassas resistentes à água, conduzem a alterações da sua cor para tom mais claro e redução de resistências mecânicas. Neste estudo avalia-se o efeito que substituições de cal aérea por uma terra local caulinítica apresentam em argamassas de cal ao traço volumétrico 1:2, correspondendo a argamassas com traço em massa de 1:8, com substituições de 10% a 50%. As argamassas têm, pela sua formulação, menor energia incorporada e demonstram ser adequadas para aplicação em rebocos de edifícios antigos e mesmo em construção nova com características compatíveis. Os resultados da caracterização mecânica, física e por ataque de sulfatos foram positivos para uma substituição de 10%, variando percentualmente entre propriedades, mas muito há ainda a investigar para um conhecimento aprofundado deste tipo de argamassas mistas de cal e terra, muito utilizadas no passado, com vista à otimização de formulações que possam vir a ser aplicadas correntemente. Abstract Earth-lime mortars probably result from professional practices from the time when economical conditions enabled the addition of air lime to vernacular earth mortars, which are not durable when in contact with water. Previous studies have shown that the addition of low contents of air lime on earth mortars with dark colour, while turning the mortars water resistant, makes their colour lighter and weakens their mechanical characteristics. This study examines the partial weight replacement of lime by a local earth in air lime mortars with a 1:2 lime: sand volumetric proportion, corresponding to mortars with a 1:8 weight proportion, with replacements from 10 to 50%. The embodied energy of mortars is reduced by their formulation, and they are adequate for use as render in old buildings and also on new constructions with compatible characteristics. The results of the mechanical and physical characteristics, as well as on the reaction to sulphates attack, were particularly positive for a 10% lime replacement by earth, with variations between the assessed properties. Nevertheless, further research is still needed for a deeper knowledge of the characteristics of lime-earth mortars, widely used in the past, in order to optimise formulations to be applied in the present day.
- Published
- 2018
12. Earth-based mortars for masonry plastering
- Author
-
Paulina Faria, Santos, Tânia, and Silva, Vitor
- Subjects
masonry ,mortar ,characterization ,clayish earth ,vegetal fibre ,plaster - Abstract
9th International Masonry Conference 2014, 7-9 July, Universidade do Minho, Guimarães Earth mortars have been applied since unknown times. Their advantages are ecological but also cover several technical aspects, in terms of compatibility with masonries, reversibility, comfort, aesthetic and health. Some requirements of a recent German standard, which focus on non-stabilized earth plastering mortars, are presented. A commercial premixed Portuguese earth mortar was made within an ECVET workshop and applied as plasters on four different experimental masonry walls, at exterior environmental conditions. The plasters were observed during six months and characterized in situ by non destructive techniques, namely by ultra-sounds and for surface hardness. The same mortar used for the plasters was characterized in laboratory in fresh state and samples of mortar (only mortar and mortar layer applied on brick) were produced and characterized after drying. The characterization of the earth plasters applied on the walls and of the mortar samples is presented and discussed, showing the viability of their use as plaster for different masonry walls.
13. Evaluating earthen mortars for rendering
- Author
-
Tânia Santos, Paulina Faria, and DEC - Departamento de Engenharia Civil
- Subjects
Oat fiber ,Physical-mechanical characterization ,Earthen plaster ,Clayish earth ,Air lime - Abstract
As it is now recognized worldwide, the use of earth mortars for plastering and rendering is very important due to eco-efficiency. Rendering mortars have to present durability to rain water. A ready-mixed earth mortar based on natural clayish earth, siliceous sand and cut oat fibers was analyzed. In addition to this, three other mortars with volumetric proportion 1:3 (clayish earth: aggregate) were formulated in laboratory. A coarse and a fine sand were used as aggregate. Oat fibers were added to one of these mortars while oat fibers plus air lime were added to another. Microstructure, mechanical strength, capillary absorption, drying and mineralogical composition were evaluated. It was concluded that the addition of a small amount of air lime causes a decrease of mechanical strength and an increase on capillary absorption. For that reason it does not seem the best technique to increase durability for rendering mortars. publishersversion published
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.