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Accelerated durability testing of wood-base fiber and particle panel materials

https://library.fpinnovations.ca/en/permalink/fpipub1494
Author
Unligil, H.H.
Date
March 1982
Edition
37999
Material Type
Research report
Field
Wood Manufacturing & Digitalization
S <33 < pd ^ ACCELERATED DURABILITY TESTING OF WOOD-BASE FIBER AND PARTICLE PANEL MATERIALS
Author
Unligil, H.H.
Date
March 1982
Edition
37999
Material Type
Research report
Physical Description
7 p.
Sector
Wood Products
Field
Wood Manufacturing & Digitalization
Research Area
Advanced Wood Manufacturing
Subject
Wood
Panels
Materials
Series Number
CFS/DSS project no 12/81-82
3-65-57-016
E-23
Location
Ottawa, Ontario
Language
English
Abstract
Composite materials - Durability
Wood-based panels
Wood-based panels - Durability
Wood Based Composites
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Advanced wood-based solutions for mid-rise and high-rise construction: analytical models for balloon-type CLT shear walls

https://library.fpinnovations.ca/en/permalink/fpipub52680
Author
Chen, Zhiyong
Cuerrier-Auclair, Samuel
Popovski, Marjan
Date
July 2018
Material Type
Research report
Field
Sustainable Construction
Author
Chen, Zhiyong
Cuerrier-Auclair, Samuel
Popovski, Marjan
Contributor
Natural Resources Canada. Canadian Forest Service
Date
July 2018
Material Type
Research report
Physical Description
83 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Building Systems
Subject
Cross Laminated Timber
Performance
Building construction
Building materials
Energy
Language
English
Abstract
Lack of research and design information for the seismic performance of balloon-type CLT shear walls prevents CLT from being used as an acceptable solution to resist seismic loads in balloon-type mass-timber buildings. To quantify the performance of balloon-type CLT structures subjected to lateral loads and create the research background for future code implementation of balloon-type CLT systems in CSA O86 and NBCC, FPInnovations initiated a project to determine the behaviour of balloon-type CLT construction. A series of tests on balloon-type CLT walls and connections used in these walls were conducted. Analytical models were developed based on engineering principles and basic mechanics to predict the deflection and resistance of the balloon-type CLT shear walls. This report covers the work related to development of the analytical models and the tests on balloon-type CLT walls that the models were verified against.
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Advanced Wood-based Solutions for Mid-rise and High-rise Construction: Structural Performance of Post-Tensioned CLT Shear Walls with Energy Dissipators

https://library.fpinnovations.ca/en/permalink/fpipub49859
Author
Chen, Zhiyong
Popovski, Marjan
Symons, Paul D.
Date
May 2018
Material Type
Research report
Field
Sustainable Construction
................................................................................................ 13 4.1.1 Materials and Methods
Author
Chen, Zhiyong
Popovski, Marjan
Symons, Paul D.
Contributor
Natural Resources Canada. Canadian Forest Service
Date
May 2018
Material Type
Research report
Physical Description
117 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Advanced Wood Materials
Subject
Cross Laminated Timber
Performance
Building construction
Building materials
Energy
Language
English
Abstract
The latest developments in seismic design philosophy have been geared towards developing of so called "resilient" or "low damage" innovative structural systems that can reduce damage to the structure while offering the same or higher levels of safety to occupants. One such innovative structural system is the Pres-Lam system that is a wood-hybrid system that utilizes post-tensioned (PT) mass timber components in both rigid-frame and wall-based buildings along with various types of energy disspators. To help implement the Pres-Lam system in Canada and the US, information about the system performance made with North American engineered wood products is needed. That information can later be used to develop design guidelines for the designers for wider acceptance of the system by the design community. Several components influence the performance of the Pres-Lam systems: the load-deformation properties of the engineered wood products under compression, load-deformation and energy dissipation properties of the dissipators used, placement of the dissiaptors in the system, and the level of post-tensioning force. The influence of all these components on the performance of Pres-Lam wall systems under gravity and lateral loads was investigated in this research project. The research project consisted on two main parts: material tests and system tests. In the material tests part of the program, a total of 110 compression tests were conducted to determine the load-deformation properties of four different engineered wood products (LVL, LSL, Glulam and CLT) in various directions. The LVL, LSL and Glulam specimens tested under compression parallel to grain had similar linear elastic behaviour with limited ductility. The CLT specimens tested under compression in the major-axis direction had linear elastic behaviour with moderate plasticity. Depending on the type of engineered wood product, typical failure modes included crushing, shear, wedge split and splitting. The compressive strength of the products tested ranged from 42.1 to 53.5 MPa, the global MOE (of the entire specimen under compression) varied between 6390 and 9554 MPa, the local (near the crushing surface) MOE parallel to grain was in the range of 2211 to 5090 MPa, while the local to global MOE ratio ranged from 29.2 to 58.0%, and was higher with the increase in the oven-dry density. The specimens of the four different engineered wood products tested under compression perpendicular to grain or in the minor-axis direction had elastic-plastic behaviour with a clearly defined plastic plateau. Crushing (densification) of the fibres perpendicular to grain was the main failure mode for all specimens, and was in some cases followed by in-plane shear failure or cracking perpendicular to grain. Compression parallel to grain in the middle layer that was followed by its delamination and buckling was a unique failure mode for CLT specimens tested under compression in the minor strength direction. The compressive strength of the engineered wood products tested were in the range of 4.8 to 27.8 MPa, while the global and local MOE perpendicular to grain were in the range of 244 to 2555 MPa, and 320 to 1726 MPa, respectively. The compressive strength and global MOE perpendicular to grain increased with an increase in the oven-dry density. The results show no well-defined trend for the local MOE perpendicular to grain. The specimens loaded in the centre perpendicular to grain had higher strength, global and local MOE than those loaded at the end. A convenient and timesaving design for the axial energy dissipators (fuses) was developed by replacing the epoxy in the original design with two half-tubes. Compared to the original design of fuses with epoxy, the new design with two half-tubes had similar necking failure mode and a longer failure displacment, thus providing user-friendly fuses that performed similar or even better than the original design. In the system tests part of the program, a total of 17 different PT and Pres-Lam CLT walls with six different configurations were tested under monotonic and reversed cyclic loading. The studied parameters included the level of PT force, the position of the fuses, and the number of UFPs. CLT shear walls subjected only to post-tensioning, had non-linear elastic behaviour. The behaviour of the PT walls with and without energy dissipators was relatively similar under monotonic and cyclic loading. The strength degradation observed during the cyclic tests was low in all wall configurations suggesting that very little damage was inflicted upon the structure during the first cycles at any deformation level. Four major failure modes, including yielding and buckling of fuse, crushing and splitting of wood at the end of wall, and buckling of lumber in the exterior-layer of CLT wall, were observed in the tests. The yielding in fuses occurred at the early stage of loading as designed and the other failure modes happened when the lateral drift reached or beyond 2.5%. The initial stiffness of the single-panel PT CLT walls tested ranged from 1.80 to 2.31 kN/mm, the load at the decompression point and 2.5% drift were in the range of 4.2 to 14.9 kN and 32.7 to 45.9 kN, respectively. The initial stiffness of the single-panel Pres-Lam CLT walls tested ranged from 1.69 to 2.44 kN/mm, the load at the decompression point and 2.5% drift were in the range of 21.0 to 30.2 kN and 59.6 to 69.8 kN, respectively. All the mechanical properties increased with an increase in the PT force. The average initial stiffness and the load at 2.5% drift of the coupled-panel Pres-Lam CLT walls tested were 4.59 kN/mm and 151.3 kN, respectively, while the load at the decompression point increased from 58.4 to 69.7 kN by increasing the number of UFP. The test results show that the behaviour of the Pre-Lam CLT shear walls can be de-coupled and a “superposition rule” can be applied to obtain the stiffness and resistance of such system. The test results gave a valuable insight into the structural behaviour of the PT and Pres-Lam CLT shear wall under in-plane lateral loads. The data from the testing will be used in the future for development of numerical computer models. They will also be used for development of design guidelines for this system. All tests conducted in this study and the analyses in the future modelling research will form the basis for developing future design guidelines for PT and Pres-Lam mass timber systems.
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Air tightness of one type of hardboard siding: first of 2 reports

https://library.fpinnovations.ca/en/permalink/fpipub5904
Author
Onysko, D.M.
Jones, S.K.
Date
March 1988
Edition
41506
Material Type
Research report
Field
Sustainable Construction
Author
Onysko, D.M.
Jones, S.K.
Date
March 1988
Edition
41506
Material Type
Research report
Physical Description
32 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Advanced Wood Materials
Subject
Siding
Measurement
Materials
Building materials
Building construction
Air
Series Number
CFS project no.15
Project no.4310C016
E-785
Location
Ottawa, Ontario
Language
English
Abstract
Air Leakage - Measurement
Siding - Hardboard
Building construction - Moisture determination
Building materials - Hardboard siding
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Air tightness of two walls sprayed with polyurethane foam insulation

https://library.fpinnovations.ca/en/permalink/fpipub5905
Author
Onysko, D.M.
Jones, S.K.
Date
March 1988
Edition
41507
Material Type
Research report
Field
Sustainable Construction
Author
Onysko, D.M.
Jones, S.K.
Date
March 1988
Edition
41507
Material Type
Research report
Physical Description
22 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Advanced Wood Materials
Subject
Walls
Testing
Measurement
Materials
Building construction
Air
Series Number
CFS project no.15
Project no.4310C016
E-786
Location
Ottawa, Ontario
Language
English
Abstract
Foam, Urethane - Testing
Insulating Materials - Moisture - Measurement
Building construction - Light frame - Testing
Walls - Air Leakage
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Analyse de la compétitivité et du positionnement des produits isolants faits à partir de fibres de bois en Amérique du Nord

https://library.fpinnovations.ca/en/permalink/fpipub2708
Author
Lavoie, P.
Date
January 2010
Edition
39314
Material Type
Research report
Field
Sustainable Construction
Author
Lavoie, P.
Date
January 2010
Edition
39314
Material Type
Research report
Physical Description
50 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Market Analysis
Subject
United States (USA)
Building materials
Canada
Markets
Series Number
Programme des technologies transformatrices ; Projet no 201000339
201000339
Location
Québec, Québec
Language
French
Abstract
La tendance vers la construction verte est en croissance fulgurante depuis les dix dernières années. On estime que le marché de la construction verte représente environ 5 % du marché actuel de la construction. La majorité des bâtiments conçus ou construits dans une perspective environnementale se situent dans les secteurs non-résidentiel ou multifamilial. C’est dans ce contexte que nous nous sommes intéressés à la possibilité de développer et vendre des isolants faits à partir de bois; un matériau généralement reconnu pour ses vertus écologiques. La principale application ciblée dans le rapport est les cavités murales. Ce rapport se présente en cinq (5) principales sections :
Marché : Le marché mondial pour les produits isolants est énorme. Il est estimé à plus de 190 milliards de pi² base R-1. Près de 70 % de ce total est destiné au marché de la construction qui comprend la construction résidentielle (45 %) et non-résidentielle (23 %). La majorité des isolants consommés à l’échelle mondiale sont utilisés en Amérique du Nord et en Europe de l’Ouest. De manière générale, le marché est dominé par les mousses plastiques et la fibre de verre. Le marché pour les isolants autres (alternatifs) oscille entre 2 et 6 % en fonction des marchés dont il est question. Cette proportion est généralement plus élevée dans la réparation et la rénovation que dans la nouvelle construction. Il existe des variations régionales qui sont documentées dans le présent rapport.
Structure industrielle : Les isolants sont des produits dont la valeur unitaire est relativement faible. Il est par conséquent difficile de livrer ces produits sur de grandes distances. La majorité de la production mondiale se fait dans les deux grands marchés mondiaux soit l’Amérique du Nord et l’Europe de l’Ouest. Le tiers du marché (33 %) est dominé par cinq grandes entreprises qui opèrent plusieurs divisions. Elles sont : St-Gobain, Rockwool, Owens Corning, Johns Manville et Knauf. Il faut dire que les produits dominant actuellement le marché nécessitent d’importants investissements en capitaux. Ceci explique, en partie, cette concentration du marché au chapitre de la production.
Politiques et réglementations : Cette section documente les grandes tendances qui risquent d’affecter la demande pour les produits isolants. L’augmentation des coûts de production des mousses pourrait offrir des opportunités pour d’autres produits. Les exigences relatives aux émissions de gaz à effet de serre pourraient jouer en faveur des isolants faits à partir de bois. Les politiques de réutilisation des matières résiduelles présentent des opportunités quant à l’utilisation de ces résidus pour fabriquer des isolants. La hausse des exigences de performance énergétique exigera l’amélioration des produits communément utilisés ainsi que des innovations à partir des matériaux moins fréquemment employés.
Performance environnementale : Cette section montre que les produits isolants à base de bois peuvent contribuer à l’obtention de 8 à 9 % des points pour les systèmes de certification LEED et Green Globes. Il faut toutefois être conscient que l’isolant représente une petite proportion des matériaux entrants dans la construction d’un immeuble (<1 % en valeur). Ceci démontre l’intérêt, du point de vue de la construction verte, à développer des produits qui ont d’autres fonctions que simplement celle d’isoler.
Comportements et exigences d’achat : Des entrevues exploratoires auprès d’architectes et autres utilisateurs d’isolant ont démontré un intérêt pour des produits plus verts. Les principaux facteurs intervenant dans la sélection du matériau isolant sont sa résistance thermique, son coût et la familiarité avec le produit. Les produits isolants conventionnels ne reçoivent que très peu d’intérêt de la part des architectes. L’isolant n’est pas perçu comme étant très innovateur (c’est plus ou moins une commodité) et a peu d’incidence sur le concept (esthétique ou fonctions) du bâtiment. Une des tendances qui semble poindre actuellement à l’horizon est celle des isolants qu’il est possible d’agrafer par l’extérieur du bâtiment. Les autres sections du document présentent le contexte dans lequel le projet s’est exécuté (contexte, objectifs, équipe de projet, etc.) et font état des conclusions à retenir (discussion et conclusions). Les propriétés et caractéristiques générales des différents matériaux isolants sont présentées en annexe. Cette section complémentaire recense des exemples de produits pour chacun des principaux types de matériaux utilisés sur le marché incluant la fibre et la laine de bois. Les informations colligées dans le cadre de ce projet permettent d’établir ces constats généraux :
À court et moyen terme, les principaux marchés pour l’isolant fait à partir de bois sont le marché non-résidentiel et multifamilial.
Le positionnement du produit isolant bois devrait être du côté des produits verts ou respectueux de l’environnement. Il ne s’agit pas d’un matériau dont la performance surpasse les matériaux communément utilisés.
Pour profiter pleinement de ce positionnement stratégique, le(s) produit(s) développé(s) devrai(en)t : o Incorporer d’autres fonctions (pare-air, pare-vapeur, pare-feu, revêtement structural extérieur, parement extérieur, structure, etc.). o Utiliser des matériaux issus de la démolition d’immeubles existants, fibres agricoles et autres intrants avec une faible empreinte écologique. o Être analysés objectivement par l’entremise d’une analyse de cycle de vie. La conclusion du rapport soulève certaines avenues de recherche pour les années à venir. Parmi celles-ci, on note les pistes suivantes :
Meilleure connaissance des types de construction les plus susceptibles d’utiliser des isolants verts faits à partir de bois.
Critères (incluant le prix et spécification de produit) recherchés par les différents utilisateurs.
Identification des marchés industriels (pas liés à la construction) susceptibles d’être réceptifs à des produits à base de bois.
Potentiel d’utilisation des matériaux de différentes sources (récupération, agricole, etc.) dans la fabrication de produits isolants.
Développement des propriétés (ex. : résistance à la compression) et des procédés.
Insulation
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Aqueous phenolic dispersions for bonding wood composites - progress report

https://library.fpinnovations.ca/en/permalink/fpipub628
Author
Troughton, G.E.
Walser, D.C.
Andersen, Axel W.
Clarke, Michael Raymond
Date
March 1990
Edition
36887
Material Type
Research report
Field
Wood Manufacturing & Digitalization
Author
Troughton, G.E.
Walser, D.C.
Andersen, Axel W.
Clarke, Michael Raymond
Date
March 1990
Edition
36887
Material Type
Research report
Physical Description
6 p.
Sector
Wood Products
Field
Wood Manufacturing & Digitalization
Research Area
Advanced Wood Manufacturing
Subject
Phenols
Materials
Gluing
Glue
Series Number
Forestry Canada No. 34
contract no.1812L005
W-782
Location
Vancouver, British Columbia
Language
English
Abstract
Glue, Phenolic
Gluing
Composite materials
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Assessing preferences for wood characteristics in visual applications

https://library.fpinnovations.ca/en/permalink/fpipub1251
Author
Fell, David
Date
April 2004
Edition
37705
Material Type
Research report
Field
Sustainable Construction
Author
Fell, David
Contributor
Natural Resources Canada. Canadian Forest Service.
Date
April 2004
Edition
37705
Material Type
Research report
Physical Description
46 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Market Analysis
Subject
Materials
Furniture
Series Number
Value to Wood No. FCC 9
W-2069
Location
Vancouver, British Columbia
Language
English
Abstract
As this is a relatively new field much of the emphasis of this study was on a literature review to help develop a theoretical platform to work from. It was found that the colour of wood appears in the literature in two ways. It appears qualitatively in marketing and value-added research, and it appears quantitatively in colour matching and quality control research. The present research study is the first known occurrence of the quantitative comparison of measured colour with measured consumer preference. There has been considerable research into character marks in wood. This research has largely been based around traditional hardwoods as the result of increasing scarcity of high grades of lumber. However, more fundamental characteristics such a grain profile, rings per inch, and the presence of visual features such as rays and vessels have not been considered with respect to visual preferences. Consumer preference data used for this study originated from the study “Consumer visual evaluation of underutilized Canadian wood species” (Fell, 2002). This was chosen as it has a great variety of species to analyze. However, in the survey consumers evaluated the species for overall appearance and not for specific end-uses. Therefore results of the current study are general to wood used in the home and do not apply to specific end-uses.
Furniture - Materials used
Flooring - Materials used
Canadian woods
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Biotechnology to improve mould, stain and decay resistance of OSB

https://library.fpinnovations.ca/en/permalink/fpipub42285
Author
Yang, D.-Q.
Wang, Xiang-Ming
Wan, Hui
Date
March 2005
Material Type
Research report
Field
Wood Manufacturing & Digitalization
for protecting OSB raw materials from biodegradation and to explore biological pre- or post-treatments
Author
Yang, D.-Q.
Wang, Xiang-Ming
Wan, Hui
Contributor
Canada. Canadian Forest Service
Date
March 2005
Material Type
Research report
Physical Description
75 p.
Sector
Wood Products
Field
Wood Manufacturing & Digitalization
Research Area
Advanced Wood Manufacturing
Subject
Materials
Series Number
Canadian Forest Service No. 31
Location
Sainte-Foy, Québec
Language
English
Abstract
This project aimed to develop technologies for protecting OSB raw materials from biodegradation and to explore biological pre- or post-treatments to increase the durability of panels so they would better resist mould, stain and decay. The project was conducted in five parts. Part one involved developing a biological technology to protect OSB raw materials from biodegradation. The results of this part of the work showed that all untreated logs, with or without bark, were seriously degraded by moulds, stain and decay fungi after a summer storage period of five months. The logs with bark were more degraded than the debarked logs, and the log ends were more degraded than the middle sections. After summer storage, 55% to 83% of the wood was degraded in untreated logs. The biological treatment was effective, only 4% to 16% of the wood in treated logs was infected by various fungi after a five-month storage period. Furthermore, the biological treatment was more effective on logs without bark than logs with bark, and more effective on yellow birch and aspen than on red maple. After one year in storage, the total infection rates of untreated logs ranged from 68% to 91%, whereas the rate for biologically treated logs ranged from 27% to 49%. Strands cut from untreated logs contained 50% to 75% of grey or blue stained strands, whereas those cut from biologically treated logs contained 10% to 25% of such strands. Panels made using biologically treated logs had the lowest thickness swelling (TS) and water absorption (WA) values compared with panels made using fresh-cut logs and untreated stored logs. The other physical and mechanical properties of the various panels made for this test were comparable. For the mould resistance, all panels made from fungal treated logs had better mould resistance than those made from freshly cut and untreated logs. Panels made of strands cut from fungal treated debarked logs had better mould resistance than the panels made from fungal treated bark-on logs. The second part of the research consisted of investigating antifungal properties of barks from various wood species. In this part, antifungal properties of barks from 6 wood species: aspen, red maple, yellow birch, balsam fir, white spruce and white cedar were screened in a laboratory test against moulds, staining fungi, white-rot and brown-rot fungi. Based on the colony growth rate of moulds, stain and decay fungi on bark-extract-agar media, white spruce bark was the best at inhibiting growth of these fungi, followed by red maple bark. White cedar and balsam fir bark somewhat inhibited certain fungi tested. Aspen and yellow birch bark did little or nothing at all to inhibit fungal growth. The third part involved developing a biological treatment technology by using naturally resistant wood species to increase the durability of panels so they would better resist mould, stain and decay. In this part, a series of tests were conducted using various wood species. These tests included a) using white cedar to improve panel durability; b) optimizing manufacturing conditions for producing durable panels with white cedar; and c) using other wood species to produce mould-resistant panels. The results showed that three-layer panels made using white cedar strands in the face layers and aspen strands in the core layer at different ratios were mould and decay resistant. White spruce heartwood-faced panels were highly mould resistant and moderately decay resistant. In addition to being mould resistant, white spruce heartwood-faced aspen panels also had better internal bond (IB), modulus of rupture (MOR) and modulus of elasticity (MOE) properties, compared with aspen panels. The panels with black spruce in surface layer had mechanical and mould-resistance properties that were similar to those with white spruce in surface. The panels with surface layer of Eastern larch heartwood were non-resistant to moulds and slightly resistant to decay, but they had better IB, TS and WA properties compared with the other types of panels. The fourth part of the research consisted of developing a biological treatment technology by using fungal antagonists to increase the durability of panels against mould, stain and decay. In this part, two major tests were conducted using various fungal species. They were: a) treating wood strands with three antagonistic fungi, Gliocladium roseum, Phaeotheca dimorphospora and Ceratocystis resinifera, to increase OSB panel durability; and b) treating wood strands with a lignin-degrading fungus, Coriolus hirsutus, to reduce OSB resin usage. The results of this part of the work showed that all of the 4 fungal species used grew well on aspen strands in four weeks, and strands in all treatments had normal wood color after incubation. For IB property, panels made of fungal treated strands were better or similar to the control panels. Panels made of fungal treated strands had higher TS and WA values than untreated control panels. For mechanical properties, panels made of fungal treated strands had a slight lower dry MOR and higher wet MOR than control panels. For mould resistance, panels made of fungal treated strands were infected by moulds one week later than the untreated control panels, and reduction of mould infection rates was detected on fungal treated panels within 6 weeks. After 6 weeks, all panels, treated or untreated, were seriously infected by moulds. Reducing resin usage in fungal treated panels did not affect panel density. Compared with untreated control panels, the IB property of panels made of fungal treated strands was slightly increased by using normal dosage of resin or a reduced dosage by 15%, but slightly decreased with a resin reduction by 30%. There was a negative linear correlation of the panel TS and WA properties with resin reduction by using fungal treated strands. For the mechanical properties, panels made of fungal treated strands had lower dry MOR and MOE values, but higher wet MOR values (except for a resin reduction of 30%) than panels made of untreated strands. The fifth part involved protecting OSB against mould and decay by post-treatment of panels with natural extracts from durable wood species and from fungal antagonists. In this part, three tests were conducted using extracts of white cedar heartwood and extracts of a fungal antagonist. These tests were: a) screening antifungal properties of natural extracts against mould and decay fungi; b) post-treating OSB panels with white cedar heartwood extracts and finishing coats; and c) post-treating OSB panels with fungal metabolites. The results of this part of the work showed that the mycelial growth of all fungi tested (moulds, staining fungi, white-rot and brown-rot fungi) was inhibited by the extracts of white cedar heartwood and extracts of the fungal antagonist, P. dimorphospora, on agar plates. Panel samples dipped with the cedar extracts got slight mould growth on the 2 faces and moderate mould growth on the 4 sides, whereas the panel samples dip-treated with the fungal extracts got the minimal mould infection among the panels tested. The results of the mould test on the post-treated panels with extracts of white cedar heartwood and three coating products showed that slight or no mould growth was detected on any sample dip-treated with the extracts and then brushed with finishing coats. The decay test showed that most post-treated samples had less weight losses than untreated control samples.
Composite materials - Durability
Biotechnology
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Biotechnology to improve mould, stain and decay resistance of OSB

https://library.fpinnovations.ca/en/permalink/fpipub42231
Author
Yang, D.-Q.
Wang, Xiang-Ming
Wan, Hui
Date
March 2004
Material Type
Research report
Field
Wood Manufacturing & Digitalization
aimed to develop technologies for protecting OSB raw materials from y of panels so logy to protect
Author
Yang, D.-Q.
Wang, Xiang-Ming
Wan, Hui
Contributor
Canada. Canadian Forest Service
Date
March 2004
Material Type
Research report
Physical Description
46 p.
Sector
Wood Products
Field
Wood Manufacturing & Digitalization
Research Area
Advanced Wood Manufacturing
Subject
Materials
Series Number
Canadian Forest Service No. 31
Location
Sainte-Foy, Québec
Language
English
Abstract
Oriented strand board (OSB) is widely used in house construction in North America. In Canada, OSB panels are commonly made of aspen strands and are susceptible to mould and decay when they get wet. Building envelope failures due to mould, decay or poor construction practices can negatively impact the image of wood. This can lead to product substitution that in turn can affect the wood industry’s overall competitiveness. To ensure durability of OSB panels, the most important consideration is the use of mould- and decay-resistant panels to prevent fungal attack. Using low environmental impact technology to improve the durability of OSB products could have market-related advantages over using chemical protection products. This project aimed to develop technologies for protecting OSB raw materials from biodegradation and to explore biological pre- or post-treatments to increase the durability of panels so they would better resist mould, stain and decay. The project was divided into three parts. Part one involved developing a biological technology to protect OSB raw materials from biodegradation. In this part, aspen, red maple and yellow birch trees, which are commonly used to make OSB in Canada, were felled in May and cut into 4-foot logs. These logs were then equally divided into two groups (16 logs each) with one group keeping its bark and the other having it removed. These debarked and “bark-on” logs were further divided into two groups, each containing 8 logs. One group of logs was treated with a bioprotectant and another group served as a control. The treated and untreated logs were stored separately in Forintek’s yard. Two inspections were conducted, one at the end of the growth season (in October after a 5-month storage period) and the other after one year. During each inspection, four logs from each test group were examined for fungal degradation (mould, stain and decay), and then cut into strands to be used for manufacturing panels. The panels’ physical and mechanical properties and mould resistance were evaluated. The second part involved developing a biological pre- or post-treatment technology by using naturally resistant wood species to increase the durability of panels so they would better resist mould, stain and decay. In this part, a series of tests were conducted using various wood species. These tests included a) determining the antifungal properties of bark from various wood species; b) using white cedar to improve panel durability; c) optimizing manufacturing conditions for producing durable panels with white cedar; d) using other wood species to produce mould-resistant panels; and e) post-treating panels with extracts of durable wood species. The third part consists of developing a biological pre- or post-treatment technology by using fungal antagonists to increase the durability of panels against mould, stain and decay. This part will be conducted in the 2004-2005 fiscal year, and results will be included in next year’s report. The results of the first part on the protection of raw materials showed that all untreated logs, with or without bark, were seriously degraded by moulds, stain and decay fungi after a summer storage period of five months. The logs with bark were more degraded than the debarked logs, and the log ends were more degraded than the middle sections. After summer storage, 55% to 83% of the wood was degraded in untreated logs. The biological treatment was effective, only 4% to 16% of the wood in treated logs was affected by various fungi after a five-month storage period. Furthermore, the biological treatment was more effective on logs without bark than logs with bark, and more effective on yellow birch and aspen than on red maple. After one year in storage, the total infection rates of untreated logs ranged from 68% to 91%, whereas the rate for biologically treated logs ranged from 27% to 49%. Among these treated logs, the logs ends were degraded from 31% to 62%, whereas the middle sections were degraded from 7% to 26%. Strands cut from untreated logs contained 50% to 75% of grey or blue stained strands, whereas those cut from biologically treated logs contained 10% to 25% of such strands. Panels made using biologically treated logs had the lowest TS and WA values compared with panels made using fresh-cut logs and untreated stored logs. The other physical and mechanical properties of the various panels made for this test were comparable. The antifungal properties of bark from six wood species (aspen, red maple, yellow birch, balsam fir, white spruce and white cedar) were investigated in the second part of this research project. Based on the colony growth rate of moulds, stain and decay fungi on bark-extract-agar media, white spruce bark was the best at inhibiting growth of these fungi, followed by red maple bark. White cedar and balsam fir bark somewhat inhibited certain fungi tested. Aspen and yellow birch bark did little or nothing at all to inhibit fungal growth. The research also showed that the white cedar heartwood-extract-agar medium not only inhibited decay fungi growth, but also inhibited the growth of moulds and staining fungi. The bark-extract-agar medium of this wood species was less effective in inhibiting fungal growth than the heartwood was. Three-layer panels made using white cedar heartwood strands in the face layers and aspen strands in the core layer at a ratio of 25:0:25 were mould and decay resistant, but the panels “blew” easily during manufacturing and their mechanical properties were not satisfying. The overall mould infection rate on white cedar heartwood-faced panels was 0.8, which indicated that the panel was mould resistant. White spruce heartwood-faced panels were highly mould resistant and moderately decay resistant. The overall mould infection rate on white spruce heartwood-faced panels was only 0.2 after 8 weeks of exposure to high humidity environmental conditions. In addition to being mould resistant, white spruce heartwood-faced aspen panels also had better IB, MOR and MOE properties, compared with aspen panels. The panels with black spruce in surface layer had mechanical and mould-resistance properties that were similar to those with white spruce in surface. The panels with surface layer of Eastern larch heartwood were non-resistant to moulds and slightly resistant to decay, but they had better IB, TS and WA properties compared with the other types of panels. The overall mould infection rate on the panel with surface layer of Eastern larch heartwood was 3.7, which was similar to the rate for aspen control panels. Aspen panels (serving as control panels) were seriously affected by moulds with overall mould infection rates ranging from 3.8 to 4.9. Aspen panels with surface layer from whole-wood strands (using both sapwood and heartwood) from white cedar, in a ratio of 25:50:25 and pressed at 220°C for 150 seconds, were well bonded and had IB, TS, WA and MOE values that were similar to those of aspen control panel, but with a higher MOR. All the panels’ properties met the requirements of the standard. This type of panel also was the least infected by moulds, especially in the face layers which rated a 0.2. The panel sides were moderately infected, rating a 2.6, this occurring mostly in the middle layer of aspen strands. The overall rate of this type of panel was 1.0, which indicated that the panels were resistant to mould infection. This type of panel was also highly resistant to brown rot and moderately resistant to white rot. Panels made of steam-treated white cedar whole-wood strands and aspen strands at a ratio of 3:7 based on oven-dry weight also had low infection rates: the average face infection rate was 1.2; the side infection was 2.4 and the overall rate was 1.6. Compared with aspen panels, this type of panel also had high MOR and MOE values and low TS and WA values. In the case of white cedar whole-wood strands faced aspen panels, when the pressing time was increased from 160 seconds to 180 seconds at 200°C, the panels’ IB strength and MOE increased whereas the panels’ TS, WA and MOR decreased. By increasing the pressing temperature from 200°C to 240°C and pressing for 160 seconds, the panels’ IB strength, MOR and MOE increased and the panels’ TS and WA decreased sharply. At a pressing temperature of 240°C and a pressing time of 180 seconds, the panels’ IB strength, MOR and MOE increased significantly and the panels’ TS and WA decreased significantly. These data showed that aspen panels with surface layer from white cedar whole strands at a ratio of 25:50:25 and pressed at 240°C for 180 seconds had the best mechanical and physical properties. All panel samples were slightly infected by moulds on the faces. A fair amount of mould occurred on the sides of panels pressed at 200°C for 160 seconds and 180 seconds and those pressed at 240°C for 180 seconds. The panels pressed at 240°C for 160 seconds were the least infected by mould (with an infection rate of 0.3). Panels pressed at 200°C had a white-yellowish colour, whereas those pressed at 240°C were yellow-brownish and darker than those pressed at 200°C. Panels pressed at 200°C for 160 or 180 seconds and those pressed at 240°C for 160 seconds were highly decay resistant, especially to brown rot. The decay resistance of panels pressed at 240°C for 180 seconds was lower compared with the other panels. Compared with aspen panels, panels with surface layer from steam-treated white cedar strands and aspen strands at a ratio of 7:3 based on oven-dry weight had higher TS, WA, MOR and MOE values and a similar IB value. Panels with surface layer from steam-treated white cedar strands and aspen strands at a ratio of 4:6 based on oven-dry weight had the highest IB value. A reduction in mould and decay resistance corresponded to a reduction in the proportion of white cedar strands in the face layers. The overall mould growth rate was 1.27 on panels with surface layer from steam-treated white cedar strands and aspen strands at a ratio of 4:6, 0.6 on panels with surface layer from steam-treated white cedar strands and aspen strands at a ratio of 7:3, and 0.4 on panels faced with 100% white cedar whole strands, respectively. Panels made from 100% white cedar whole-wood strands or a mixture of whole-wood strands of white cedar and aspen (50:50) in the core layer were “blown” after pressing. Panels made from a mixture of white cedar and aspen strands at a ratio of 25:75 in the core layer and aspen strands in the face layers had superior IB, MOR and MOE values than other panels. However, their TS and WA values were also higher than those of white cedar-faced panels. Panels made from a mixture of white cedar and aspen strands at a ratio of 25:75 in the core layer and white cedar strands in the face layers had the worst physical and mechanical properties among all the panels made for this test. The tests results for mould showed that panels made with a mixture of white cedar and aspen strands at a ratio of 25:75 in the core layer and aspen strands in the face layers ware seriously attacked by moulds and had an overall mould growth rate of 4.2. No mould infection was found on panels made from 100% white cedar strands. Panels made from a strand mixture of white cedar (50%) and aspen (50%) in the core layer and white cedar strands in the face layers had little mould infection. The overall mould growth rate on this type of panel was 0.2. Compared with the control aspen panels, aspen panels with surface layer from white cedar whole-wood strands at a ratio of 15:70:15 had similar IB and TS values, a lower WA value and higher MOR and MOE values. When the white cedar strand proportion in the face layer was increased from 15% to 25%, the panels’ IB strength and WA decreased, but their MOR and MOE values increased. Panels with surface layer from white cedar strands at a ratio of 15:70:15 had little infection from moulds on the face and bottom layers, but had an increased infection rate on all four sides. The average overall infection rate of this type of panel was 0.5. When the white cedar in the panels’ face layer was increased from 15% to 25%, the average infection rate on the panels’ faces was still 0.1, but the infection rate of the panels’ sides dropped from 1.2 to 1.0. The overall rate was 0.4. In terms of decay resistance, panels with surface layer from 25% white cedar strands performed better than those with surface layer from 15% white cedar.
Composite materials - Durability
Biotechnology
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