In fiscal year 2019-2020, FPInnovations developed a research roadmap in order to explore, test, and deploy innovative products, technologies, tools, processes, and practices that have the potential to enable the transformation of the Canadian building industry towards higher levels of industrialized construction (prefabricated off-site construction), in close collaboration with its partners.
FPInnovations a effectué un essai en laboratoire afin d’étudier la teneur en humidité (TH) du bois lamellé-croisé (CLT) découlant du coulage de chapes de béton, et l’efficacité avec laquelle un enduit imperméabilisant et une membrane permettent de de prévenir cette humidification.
FPInnovations conducted a laboratory test to investigate the potential wetting of cross-laminated timber (CLT) from the pouring of concrete topping, and the effectiveness of a water repellent coating and membrane in preventing such wetting.
Cross-Laminated Timber (CLT) is an engineered mass timber product manufactured by laminating dimension lumber in layers with alternating orientation using structural adhesives. It is intended for use under dry service conditions and is commonly used to build floors, roofs, and walls. Because prolonged wetting of wood may cause staining, mould, excessive dimensional change (sometimes enough to fail connectors), and even result in decay and loss of strength, construction moisture is an important consideration when building with CLT. This document aims to provide technical information to help architects, engineers, and builders assess the potential for wetting of CLT during building construction and identify appropriate actions to mitigate the risk.
The biomass yield per hectare predicted for the Dawson Creek TSA is 32.3 oven-dried tonnes per hectare (odt/ha) from harvest residues. The biomass ratio, which is the ratio of recovered biomass to recovered merchantable roundwood, is estimated at 19.2%. Over the next 10 years at total of 1.59 million odt of available biomass are predicted to be generated by harvest in the Dawson Creek TSA, or approximately 160,000 odt/yr. Of this, approximately 1,242,000 odt in total, or 124,000 odt/yr, is expected to be available at the economic price of $60 per oven-dried tonne. Approximately 98% of the total predicted volume is expected to be available at $90/odt: a total of 1.56 million odt, or 156,000 odt/yr.
In the construction of buildings, the timber-concrete (TCC) system can be a cost-competitive solution for floors with longer spans, since the mechanical properties of the two materials are used efficiently. Furthermore, the additional mass from the concrete improves the acoustic performance compared to a timber floor system alone. Nevertheless, TCC floors are not commonly used in buildings in Canada, due to the absence of technical guidelines for such types of structural systems in this country.
The fire resistance of cross-laminated timber (CLT) could be improved by treating the lamina with fire retardants. The major issues with this technology are the reduced bondability of the treated lamina with commercial adhesives. This study assessed several surface preparation methods that could improve the bondability and bond durability of fire-retardant treated wood with two commercial adhesives. Four surface preparation methods, including moisture/heat/pressure, surface planing, surface chemical treatment, and surface plasma treatment were assessed for their impact on the bondability and bond durability of lodgepole pine lamina. The block shear test results indicated that all surface preparation methods were somewhat effective in improving bond performance of fire-retardant treated wood compared to the untreated control wood samples, depending on the types of fire retardants and wood adhesives applied in the treatment process and bonding process. The selection of surface preparation, fire retardant, and wood adhesive should be considered interactively to obtain the best bond properties and fire performance. It may be possible to effectively bond the treated lamina with PUR adhesive without any additional surface preparation for the fire retardant used in the treatment at FPInnovations.
Mass timber is a generic name for a broad range of thick and heavy wood products such as cross-laminated timber (CLT), dowel-laminated timber (DLT), nail-laminated timber (NLT), and gluelaminated timber (GLT), among others. So far, vibration-controlled design methods have been developed mostly for CLT floors.
La construction massive en bois est un terme générique qui englobe une grande variété de produits du bois épais et lourds, notamment le bois lamellé-croisé (CLT), le bois lamellé-goujonné (DLT), le bois lamellé-cloué et le bois lamellé-collé (GLT). À ce jour, les méthodes de conception à vibrations contrôlées ont surtout été élaborées pour les planchers en CLT.