Synthesis of the Current Knowledge Concerning the Construction of French Traditional Cob Building for Giving Recommendations

Abstract:

The museum of the “Bourrine du bois Juquaud” is a tourist site located in the town of Saint Hilaire de Riez in France. It presents the daily life of the inhabitants of the marsh in the early twentieth century and their traditional earthen houses called Bourrine. The Bourrine is a cob construction with reed roof. The earth used for walls is soil from marshlands added with dune sand and straw fibres but some part are without fibres like coating applied on walls. By now, the knowledge acquired on the implementation of these mixtures for the lifting of the walls are oral knowledge and it is necessary to ensure the preservation of this traditional heritage. Currently the done reparations present cracks due to shrinkage. This study aims at well defining the mixtures by a scientific approach. The earth and dune sand were analyzed by taking cores from different existing bourrines and also by extracting soil on site. Different mixtures were produced by varying the proportion of earth sand and water. The linear shrinkage were measured. Corrections were done to get the best mixture for manufacturing and repairing the Bourrines.

• Periodical: Construction Technologies and Architecture (Volume 1)
• Pages: 620-626
• DOI: https://doi.org/10.4028/www.scientific.net/CTA.1.620
• Online since: January 2022
• Authors: Stéphanie Bonnet*, Darwish Alzeort, Philippe Poullain
• Keywords: Cob, Dune Sand, Knowledge, Shrinkage, Straw, Traditional Construction

References

[1] Barnaure, M., Bonnet S., Poullain P., Earth buildings with local materials: assessing the variability of properties measured using non-destructives methods, submitted for second reviewing in CBM journal, January (2021).

DOI: 10.1016/j.conbuildmat.2021.122613

[2] Bouhicha, M., Aouissi, F., & Kenai, S. (2005). Performance of composite soil reinforced with barley straw. Cement and concrete composites, 27(5), 617-621.

DOI: 10.1016/j.cemconcomp.2004.09.013

[3] Caue de la vendée, Conseil d'Architecture, d'Urbanisme et de l'Environnement de la Vendée, (2014), "Bien construire sur le littoral vendéen, https://www.caue85.com/.

DOI: 10.3406/noroi.1986.4349

[4] Danso, H., Martinson, D. B., Ali, M., & Williams, J. (2015). Effect of fibre aspect ratio on mechanical properties of soil building blocks. Construction and Building Materials, 83, 314-319.

DOI: 10.1016/j.conbuildmat.2015.03.039

[5] Hamard, E., Cazacliu, B., Razakamanantsoa, A., & Morel, J. C., 2016, Cob, a vernacular earth construction process in the context of modern sustainable building. Building and environment, 106, 103-119.

DOI: 10.1016/j.buildenv.2016.06.009

[6] Harries R., Saxton B., and Coventry K., 1995, The geological and geotechnical properties of earth material from central Devon in relation to its suitability for building in Cob, Geosci. South-West Engl., n°4, p.441–444.

[7] Kouakou, C. H. & Morel, J. C. (2009). Strength and elasto-plastic properties of non-industrial building materials manufactured with clay as a natural binder. Applied Clay Science, 44(1-2), pp.27-34.

DOI: 10.1016/j.clay.2008.12.019

[8] Miccoli, L., Müller, U. & Fontana, P. (2014). Mechanical behaviour of earthen materials: a comparison between earth block masonry, rammed earth and cob. Construction and Building Materials, 61, pp.327-339.

DOI: 10.1016/j.conbuildmat.2014.03.009

[9] NF EN ISO 17892-4 :2018 Geotechnical investigation and testing - Laboratory testing of soil - Part 4: Determination of particle size distribution - Reconnaissance et essais géotechniques - Essais de laboratoire sur les sols - Partie 4: Détermination de la distribution granulométrie des particules - ISO (the International Organization for Standardization), European Committee for Standardization (CEN).

DOI: 10.3403/30295182u

[10] Phung T., Formulation and characterisation of an earth-plant fibre composite: the cob,, 2018, PhD thesis in french, Normandie Université France.

[11] Quagliarini, E. & Lenci, S., 2010, The influence of natural stabilizers and natural fibres on the mechanical properties of ancient Roman adobe bricks. Journal of Cultural Heritage, 11(3), pp.309-314.

DOI: 10.1016/j.culher.2009.11.012

[12] Rojat, F., Hamard, E., Fabbri, A., Carnus, B., & McGregor, F. (2020). Towards an easy decision tool to assess soil suitability for earth building. Construction and Building Materials, 257, 119544.

DOI: 10.1016/j.conbuildmat.2020.119544