Incorporation of Natural Fibres in Rendering Mortars for the Durability of Walls
One of the main functions of renders, together with the overall aesthetic appearance of the building, is the protection of the walls against external aggressive actions, such as water, salts solutions, erosion, and mechanical impacts. However, some anomalies of renders may drastically hinder their p...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-06-01
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| Series: | Infrastructures |
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| Online Access: | https://www.mdpi.com/2412-3811/6/6/82 |
| _version_ | 1827690878891720704 |
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| author | Cinthia Maia Pederneiras Rosário Veiga Jorge de Brito |
| author_facet | Cinthia Maia Pederneiras Rosário Veiga Jorge de Brito |
| author_sort | Cinthia Maia Pederneiras |
| collection | DOAJ |
| description | One of the main functions of renders, together with the overall aesthetic appearance of the building, is the protection of the walls against external aggressive actions, such as water, salts solutions, erosion, and mechanical impacts. However, some anomalies of renders may drastically hinder their protection ability. In fact, cracking, high water permeability, and loss of adherence to the substrate of renders limit their barrier effect and favour the exposure of the substrate to external actions. The incorporation of fibres in mortars is commonly pointed out to reduce their cracking susceptibility, due to the probable enhancement in tensile strength and ductility of the composite. The use of lime in substitution of the part of the cement binder is seen as a method to reduce the modulus of elasticity and therefore enhance the resistance to cracking due to drying shrinkage. Therefore, this study investigates the wall protection-related properties of natural fibre-reinforced renders with cement-lime as a binary binder at 1:1:6 volumetric ratio. With this purpose, wool, coir, and flax fibres are used at 20% by total mortar volume and the water behaviour, cracking susceptibility, and adherence to the substrate of the mortars are assessed. Specifically, the water absorption by capillarity, drying rates, permeability to water under pressure, adherence strength, and shrinkage are evaluated. In order to evaluate the renders’ durability and therefore the durability of the protection to the walls, an artificial accelerated ageing test is performed based on heating-freezing and humidification-freezing cycles. The results indicate that the fibres’ addition reduced the shrinkage and modulus of elasticity of the mortars, which suggests lower susceptibility to cracking. The addition of fibres in mortars seemed to slightly affect their water performance and only at early ages. From the results, it was concluded that the adherence strength is not affected by the fibres’ incorporation. The fibres seem also to reduce the impacts of the ageing cycles on the mortar and the improvements provided by the fibres’ addition to the mortars’ performance remained after ageing when compared to the mortars without fibres, thus being a potential alternative to increase their durability. These aspects are particularly important for buildings, since they can extend their service life and promote their sustainability. |
| first_indexed | 2024-03-10T10:48:11Z |
| format | Article |
| id | doaj.art-d205bb80f100487b85a30cbb0e58923d |
| institution | Directory Open Access Journal |
| issn | 2412-3811 |
| language | English |
| last_indexed | 2024-03-10T10:48:11Z |
| publishDate | 2021-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Infrastructures |
| spelling | doaj.art-d205bb80f100487b85a30cbb0e58923d2023-11-21T22:26:15ZengMDPI AGInfrastructures2412-38112021-06-01668210.3390/infrastructures6060082Incorporation of Natural Fibres in Rendering Mortars for the Durability of WallsCinthia Maia Pederneiras0Rosário Veiga1Jorge de Brito2CERIS, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1, 1049-001 Lisbon, PortugalNational Laboratory for Civil Engineering, Av. do Brasil 101, 1700-066 Lisbon, PortugalCERIS, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1, 1049-001 Lisbon, PortugalOne of the main functions of renders, together with the overall aesthetic appearance of the building, is the protection of the walls against external aggressive actions, such as water, salts solutions, erosion, and mechanical impacts. However, some anomalies of renders may drastically hinder their protection ability. In fact, cracking, high water permeability, and loss of adherence to the substrate of renders limit their barrier effect and favour the exposure of the substrate to external actions. The incorporation of fibres in mortars is commonly pointed out to reduce their cracking susceptibility, due to the probable enhancement in tensile strength and ductility of the composite. The use of lime in substitution of the part of the cement binder is seen as a method to reduce the modulus of elasticity and therefore enhance the resistance to cracking due to drying shrinkage. Therefore, this study investigates the wall protection-related properties of natural fibre-reinforced renders with cement-lime as a binary binder at 1:1:6 volumetric ratio. With this purpose, wool, coir, and flax fibres are used at 20% by total mortar volume and the water behaviour, cracking susceptibility, and adherence to the substrate of the mortars are assessed. Specifically, the water absorption by capillarity, drying rates, permeability to water under pressure, adherence strength, and shrinkage are evaluated. In order to evaluate the renders’ durability and therefore the durability of the protection to the walls, an artificial accelerated ageing test is performed based on heating-freezing and humidification-freezing cycles. The results indicate that the fibres’ addition reduced the shrinkage and modulus of elasticity of the mortars, which suggests lower susceptibility to cracking. The addition of fibres in mortars seemed to slightly affect their water performance and only at early ages. From the results, it was concluded that the adherence strength is not affected by the fibres’ incorporation. The fibres seem also to reduce the impacts of the ageing cycles on the mortar and the improvements provided by the fibres’ addition to the mortars’ performance remained after ageing when compared to the mortars without fibres, thus being a potential alternative to increase their durability. These aspects are particularly important for buildings, since they can extend their service life and promote their sustainability.https://www.mdpi.com/2412-3811/6/6/82durabilitynatural fibre-reinforced mortarcement-lime mortarssustainabilityrender |
| spellingShingle | Cinthia Maia Pederneiras Rosário Veiga Jorge de Brito Incorporation of Natural Fibres in Rendering Mortars for the Durability of Walls Infrastructures durability natural fibre-reinforced mortar cement-lime mortars sustainability render |
| title | Incorporation of Natural Fibres in Rendering Mortars for the Durability of Walls |
| title_full | Incorporation of Natural Fibres in Rendering Mortars for the Durability of Walls |
| title_fullStr | Incorporation of Natural Fibres in Rendering Mortars for the Durability of Walls |
| title_full_unstemmed | Incorporation of Natural Fibres in Rendering Mortars for the Durability of Walls |
| title_short | Incorporation of Natural Fibres in Rendering Mortars for the Durability of Walls |
| title_sort | incorporation of natural fibres in rendering mortars for the durability of walls |
| topic | durability natural fibre-reinforced mortar cement-lime mortars sustainability render |
| url | https://www.mdpi.com/2412-3811/6/6/82 |
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