Abstract
Earth construction, including the use of earth mortars, has been extensively used in the past. However, with the appearance of hydraulic binders, the use of earth strongly decreased for new construction and even to repair old earth buildings, whose best solution would be the use of compatible materials such as earth mortars.
Due to the innumerable advantages of earth and with the growing concern on eco-efficient construction, the interest on earth construction has resurfaced, namely on earth mortars.
In order to optimize the composition of an earth plastering mortar made with a defined clayish earth and two siliceous sands with different particle size, six compositions were assessed. Mortars with different volumetric ratios were applied in two different supports (on the back of a tile and on a brick) and planar specimens were also produced. Distinct characteristics were assessed, such as their visual appearance, shrinkage, surface cohesion, surface hardness, dry abrasion resistance, ultrasonic velocity, adhesive strength and thermal conductivity.
It is possible to conclude that a higher clay content in the earth mortar composition increases the shrinkage and occurrence of cracking, the use of fine sand promotes high mass loss by abrasion, and the same mortar applied in different supports behave differently in terms of durability.References
Bruno P, Faria P, Candeias A, et al. Earth mortars use on pre-historic habitat structures in south Portugal Case studies. Journal of Iberian Archaeology, 2010, 13: 51–67. https://run.unl.pt/handle/10362/9954?locale=en
Cantù M, Giacometti F, Landi AG, et al. Characterization of XVIIIth century earthen mortars from Cremona (Northern Italy): Insights on a manufacturing tradition. Materials Characterization, 2015, 103: 81–89. http://dx.doi.org/10.1016/j.matchar.2015.03.018
Maddison M, Mauring T, Kirsimäe K, et al. The humidity buffer capacity of clay-sand plaster filled with phytomass from treatment wetlands. Building and Environment, 2009, 44(9): 1864–1868. https://doi.org/10.1016/j.buildenv.2008.12.008
Darling EK, Cros CJ, Wargocki P, et al. Impacts of a clay plaster on indoor air quality assessed using chemical and sensory measurements. Building and Environmental, 2012, 57: 370–376. http://dx.doi.org/10.1016/j.buildenv.2012.06.004
Gomes MI, Faria P, Gonçalves TD. Earth-based mortars for repair and protection of rammed earth walls. Stabilization with mineral binders and fibers. Journal of Cleanner Production, 2016, 172: 2401–2414. https://doi.org/10.1016/j.jclepro.2017.11.170
Melià P, Ruggieri G, Sabbadini S, et al. Environmental impacts of natural and conventional building materials: a case study on earth plasters. Journal of Cleanner Production, 2014, 80: 179–186. http://dx.doi.org/10.1016/j.jclepro.2014.05.073
Cagnon H, Aubert JE, Coutand M, et al. Hygrothermal properties of earth bricks. Energy and Building, 2014, 80: 208–217. http://dx.doi.org/10.1016/j.enbuild.2014.05.024
Emiroğlu M, Yalama A, Erdoğdu Y. Performance of ready-mixed clay plasters produced with different clay/sand ratios. Applied. Clay Science, 2015, 115: 221–229. http://dx.doi.org/10.1016/j.clay.2015.08.005
Lima J, Faria P, Santos Silva A. Earthen Plasters Based on Illitic Soils from Barrocal Region of Algarve: Contributions for Building Performance and Sustainability. Key Engineering Materials, 2016, 678: 64–77. https://doi.org/10.4028/www.scientific.net/KEM.678.64
Liuzzi S, Stefanizzi P. Experimental Investigation on Lightweight and Lime Stabilized Earth Composites. Key Engineering Materials, 2015, 666: 31–45. https://doi.org/10.4028/www.scientific.net/KEM.666.31
Randazzo L, Montana G, Hein A, et al. Moisture absorption, thermal conductivity and noise mitigation of clay based plasters: The influence of mineralogical and textural characteristics. Applied. Clay Science, 2016, 132–133: 498–507. https://dx.doi.org/10.1016/j.clay.2016.07.021
Bruno AW, Gallipoli D, Perlot C, et al. Effect of stabilisation on mechanical properties, moisture buffering and water durability of hypercompacted earth. Construction and Building Materials, 2017, 149: 733–740. https://dx.doi.org/10.1016/j.conbuildmat.2017.05.182
Maskell D, Thomson A, Walker P, et al. Determination of optimal plaster thickness for moisture buffering of indoor air. Building and Environmental, 2018, 130: 143–150. https://doi.org/10.1016/j.buildenv.2017.11.045
Hamard E, Morel JC, Salgado F, et al. A procedure to assess the suitability of plaster to protect vernacular earthen architecture. Journal of Culure. Heritage, 2013, 14(2): 109–115. https://dx.doi.org/10.1016/j.culher.2012.04.005
Delinière R, Aubert JE, Rojat F, et al. Physical, mineralogical and mechanical characterization of ready-mixed clay plaster. Building and Environmental, 2014, 80: 11–17. https://dx.doi.org/10.1016/j.buildenv.2014.05.012
Faria P, Santos T, Aubert JE. Experimental Characterization of an Earth Eco-Efficient Plastering Mortar. Journal of Materials in Civil Engineering, 2016, 28(1): 04015085. https://doi.org/10.1061/(ASCE)MT.1943-5533.0001363
Faria P, Santos T, Silva V. Earth-based mortars for masonry plastering. Proceedings of the 9IMC - 9th International Masonry Conference, 7-9 July 2014, Guimarães, CD-Rom. https://run.unl.pt/handle/10362/12495
Lima J, Faria P. Eco-Efficient Earthen Plasters: The Influence of the Addition of Natural Fibers. in Natural Fibres: Advances in science and technology towards industrial applications, RILEM Bookseries. 2016, Fangueiro R,. Rana S (ed), Springer Netherlands, 12: 315–327. https://doi.org/10.1007/978-94-017-7515-1_24
Santos T, Faria P, Santos Silva A. Avaliação in situ do comportamento de rebocos exteriores de argamassas de terra com baixas adições de cais. Conservar Património, 2017, 26: 11–21. https://doi.org/10.14568/cp2016022
EN 459-1. Building lime, Part 1: definitions, specifications and conformity criteria. 2010, CEN, Brussels.
Gomes MI, Gonçalves TD, Faria P. Characterization of Earth-Based Mortars for Rammed Earth Repair. In Earth construction & tradition. 2016, V. Feiglstorfer, Hubert IVA-ICRA Institute for comparative Research in Architecture (ed). Viena, 257–273. https://run.unl.pt/handle/10362/17059
Faria P, Silva V, Jamú N, et al. Evaluation of air lime and clayish earth mortars for earthen wall renders. In Vernacular Heritage and Earthen Architecture: Contributions for Sustainable Development. 2014, 407–413. https://run.unl.pt/handle/10362/11252
EN 1097-3. Tests for mechanical and physical properties of aggregates, Part 3: Determination of loose bulk density and voids. 1998, CEN, Brussels.
EN 1015-1. Methods of test for mortar for masonry, Part 1: Determination of particle size distribution (by sieve analysis). 1998/2006, CEN, Brussels.
E196. Particle size analysis (by dry sieving and sedimentation) (in Portuguese). 1966, LNEC, Lisbon.
DIN EN 4102-1. Fire behaviour of building materials and elements, Part 1: Classification of building materials. Requirements and testing. 1998, DIN, Berlin.
EN 998-1. Specification for mortar for masonry, Part 1: Rendering and plastering mortar. 2010, CEN, Brussels.
DIN 18947. Earth plasters – Terms and definitions, requirements, test methods (in German). 2013, DIN, Berlin.
Vissac A, Bourgès A, Gandreau D, et al. Argiles & biopolymers. Les stabilisants naturels pour la construction en terre. 2017, CRAterre, Villefontaine.
Drdácký M, Lesák J, Niedoba K, et al. Peeling tests for assessing the cohesion and consolidation characteristics of mortar and render surfaces. Materials and Structures, 2015, 48(6): 1947–1963. https://doi.org/10.1617/s11527-014-0285-8
ASTM D2240. Standard test method for rubber property – durometer hardness. 2000, ASTM, United States.
Malanho S, Veiga R. Laboratory and in situ analysis of mechanical behaviour of ready-mixed cement coatings (in Portuguese). Proceedings of the 3o Congresso Português de Argamassas Construção - APFAC, 2010, Lisbon, CD-Rom.
EN 12504-4. Testing concrete in structures, Part 4: Determination of ultrasonic pulse velocity. 2004, CEN, Brussels.
EN 1015-12. Methods of test for mortar for masonry, Part 12: Determination of adhesive strength of hardened rendering and plastering mortars on substrates. 2000, CEN, Brussels.
Gomes M, Faria P. Repair mortars for rammed earth constructions. In 12th Internacional Conference on Durability of Building Materials and Components (XII DBMC). 2011, Freitas VP, Corvacho H, Lacasse M (ed), FEUP Edições, 12-15 April, Porto, 2: 689-696. https://run.unl.pt/handle/10362/9938
Röhlen U. Mould on clay renders. In 6th International Conference on Building with Earth, LEHM 2012, Dachverband Lehm e.V., Weimar, Germany 2012, 113–121.
Ashour T, Wu W. An experimental study on shrinkage of earth plaster with natural fibres for straw bale buildings. International Journal of Sustainable Engineering, 2010, 3(4): 299–304. https://doi.org/10.1080/19397038.2010.504379
Laborel-Préneron A, Aubert JE, Magniont C, et al. Plant aggregates and fibers in earth construction materials: A review. Construction and Building Materials, 2016, 111: 719–734. https://dx.doi.org/10.1016/j.conbuildmat.2016.02.119
Botas S, Veiga R, Velosa V. Air lime mortars for conservation of historic tiles : Bond strength of new mortars to old tiles. Construction and Building Materials, 2017, 145: 426–434. https://dx.doi.org/10.1016/j.conbuildmat.2017.04.027