Sorption du produit de traitement de bois par l'argile dans la construction en terre : cas de l'octaborate disodique tétrahydraté (DOT)

Abstract

Raw earth construction provides a positive environmental balance and is ideal for ecological architecture. Cob is a material and a technique for filling a load-bearing wooden structure, halftimbering. It must have a bearing capacity to be able to support the building load. In this project the wood was treated with disodium octaborate tetrahydrate (DOT), which protects it against biological degradation agents and fire. The goal of this study is to evaluate the ability of wood to maintain its durability when in contact with cob as a function of time, external conditions (temperature, humidity), and direction of filling. The first results obtained as a function of time show a decreasing DOT migration profile in the clay from the part in direct contact with the wood to the surface part. This profile tends to disappear when the contact time exceeds 2 months. The long-term test showed that the amount of DOT absorbed tends to stabilize over time even if the initial DOT concentration is different. The results as a function of humidity show that the latter does not have a significant effect on the amount of DOT absorbed by the clay. The results as a function of humidity show that the latter does not have a significant effect on the amount of DOT absorbed by the clay. To identify the different phases, present and to determine the microstructural changes caused by the treatment and the contact with clay, a spectroscopic study was carried out on some samples of treated wood with and without contact with clay as well as on some samples of untreated wood. From this study, we could not detect the presence of boron on fir in a statistically significant way whereas the results for spruce allowed us to identify the mechanism of operation of the clay on the wood.

Date	8 Jan 2023
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Claudiane Ouellet-Plamondon (Supervisor)