Effect of bio-stabilizers on capillary absorption and water vapour transfer into raw earth

Abstract

While raw earth can be used as a structural material, its water sensitivity limits its use in modern construction. Earth has a strong affinity with water. Both water imbibition and water vapour transfer have to be taken into consideration. This affinity can be a positive point to regulate indoor ambience, but it can also negatively affect earth's mechanical properties. To avoid this possible detrimental effect, bio-based additions are used all around the world to stabilize, protect from water and enhance the mechanical properties of earth-based building materials. Biobased stabilizers have to limit liquid water absorption and maintain mechanical properties without acting as a water vapour barrier that can lead to durability issues. In this article, capillary water absorption and water vapour permeability 3 measurements are performed for combinations of various earths and bio-based additions (linseed oil, xanthan gum, casein, alginate and tannins). Linseed oil and xanthan gum help to protect the earth-based samples from absorbing liquid water without affecting the water vapour transfer in these materials.

Erosion Behaviour of Bio-Stabilised Earthen Materials

“…This soil has a plasticity index of 16.5%, a liquid limit of 46.2% and a plasticity limit of 29.7%. These soils were already studied in previous works (Guihéneuf et al, 2019;Menasria et al, 2017bMenasria et al, , 2017aPerrot et al, 2018;Guihéneuf et al, 2020bGuihéneuf et al, , 2020a.…”

“…Alternatively, the use of bio-based additions seems to be an interesting option. Some previous studies already highlighted that using bio-based additions in order to efficiently stabilize raw earth materials (Achenza and Fenu, 2006;Anger, 2011;Banakinao et al, 2016;Dove et al, 2016;Galán-Marín et al, 2010;Guihéneuf et al, 2020bGuihéneuf et al, , 2019Hafshejani et al, 2016;Menasria et al, 2017b;Nakamatsu et al, 2017;Ouedraogo, 2019;Vissac et al, 2017). This paper shows the ability of specific bio-based additions to increase the erosion resistance, which is a key parameter for both service ability and durability of compressed earth block (CEB).…”

Bioconservation of Historic Stone Buildings—An Updated Review

“…Consolidants are then applied to the stone surface using techniques such as spraying, brushing or partial immersion, or mixed with other materials to yield composites [22]. Biopolymers alter mechanical properties of building materials and their water absorption and diffusion behavior, thus increasing cohesion and enhancing mechanical properties [23]. Bioconsolidation is also achieved by direct or indirect application of microorganisms and/or their metabolites [24].…”

Thermal Properties of Eco-Friendly Earthen Materials Stabilized with Bio-Based Polymers: Experimental Data and Modeling Procedure for Improving Mix-Design

“…The incorporation of natural polymers for stabilizing earth has long been a practice embedded in construction traditions. The extensive research conducted over the past two decades has consistently demonstrated the capacity of these materials to enhance the mechanical properties, permeability, and water resistance of earth [ 66 , 68 , 69 , 70 , 71 , 72 , 73 , 74 ].…”