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Bonding Performance of Adhesive Systems for Cross-Laminated Timber Treated with Micronized Copper Azole Type C (MCA-C)

https://research.thinkwood.com/en/permalink/catalogue2200
Year of Publication
2020
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Lim, Hyungsuk
Tripathi, Sachin
Tang, Juliet
Publisher
ScienceDirect
Year of Publication
2020
Country of Publication
Netherlands
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Preservatives
Micronized Copper Azole-Type C
Bonding Performance
Delamination Tests
Block Shear Tests
Adhesives
Block Shear Strength
Wood Failure Percentage
Language
English
Research Status
Complete
Series
Construction and Building Materials
Summary
The feasibility of manufacturing cross-laminated timber (CLT) from southern yellow pine (United States grown) treated with micronized copper azole type C (MCA-C) preservative was evaluated. Lumber (2x6 visually graded no. 2 boards) was treated to two retention levels (1.0 and 2.4 kg/m3 ), planed to a thickness of 35 mm, and assembled along with an untreated control group using three adhesive systems following product specifications: melamine formaldehyde (MF), resorcinol formaldehyde (RF), and one-component polyurethane (PUR). Block shear and delamination tests were conducted to examine the bonding performance in accordance with ASTM D905 and ASTM D2559 Standards, respectively. One-way analysis of variance and Kruskal-Wallis H test were conducted to evaluate the effects of preservative retention and adhesive type on block shear strength (BSS) and wood failure percentage (WFP). Regardless of adhesive type, the 1.0 kg/m3 retention treatment significantly lowered BSS compared to the untreated control. CLT composed of the laminations treated at 2.4 kg/m3 maintained BSS when PUR and RF were used but not MF. The average WFP of each CLT configuration ranged from 89% to 99%. The untreated CLT specimens did not experience any delamination under accelerated weathering cycles. The delamination rates of the treated specimens assembled using MF and RF increased with the preservative retention level, while PUR provided delamination rates less than 1% to the laminations treated at both levels. These combined data suggest that, under the conditions tested, PUR provided overall better bonding performance than MF and RF for MCA-C treated wood.
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Durability of Cross Laminated Timber Against Termite Damage

https://research.thinkwood.com/en/permalink/catalogue1967
Year of Publication
2018
Topic
Serviceability
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
França, Tamara S.F.A.
Stokes, C. Elizabeth
Tang, Juliet
Year of Publication
2018
Country of Publication
Japan
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Serviceability
Keywords
Subterranean Termites
Mass Loss
Visual Rating
Language
English
Conference
International Convention of Society of Wood Science and Technology
Research Status
Complete
Summary
Mass timber is a category of framing components that can be built with a variety of materials. Engineered wood products have become the backbone of the mass timber movement. Some of the most common mass timber structural elements used in buildings are glue-laminated beams (glulam), laminated veneer lumber (LVL) and cross laminated timber (CLT). However, wood is a natural material which is susceptible to decay and termite attack...
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Evaluation of Cross-Laminated Timber Resistance to Termite Attack

https://research.thinkwood.com/en/permalink/catalogue1964
Year of Publication
2018
Topic
Serviceability
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
França, Tamara S.F.A.
Stokes, C. Elizabeth
Tang, Juliet
Year of Publication
2018
Country of Publication
United States
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Serviceability
Keywords
Subterranean Termites
Mass Timber
Mass Loss
Visual Rating
Language
English
Conference
American Wood Protection Association Annual Meeting
Research Status
Complete
Summary
Cross laminated timber (CLT) is a relatively recent addition to the North American timber construction market. CLT has been successfully used for construction in Europe and, in the past few years, manufacturers have looked forward to expanding the use of this product into the North American market. However, no termite susceptibility experiments have been published for the product and no standards exist for testing of the CLT and other mass timber products against termites. It is extremely important to evaluate the resistance to degradation of CLT, especially if the manufacturers are trying to implement this product in areas where the occurrence of termite infestation is high...
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Ongoing Termite Studies on Cross Laminated Timber (CLT) Panels

https://research.thinkwood.com/en/permalink/catalogue2395
Year of Publication
2019
Topic
Serviceability
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Stokes, C. Elizabeth
França, Tamara S.F.A.
Tang, Juliet D.
Year of Publication
2019
Country of Publication
United States
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Serviceability
Keywords
Subterranean Termites
Mass Timber
Mass Loss
Laboratory Assay
Language
English
Research Status
Complete
Series
Proceedings, American Wood Protection Association
Summary
The development of composite mass timber products in the late 20th century continues to generate new developments in the design and production of multi-layer wood products in a wide variety of orientations and for a wide variety of uses. In the US Congress’ Agricultural Act of 2014, provisions were specified in Section 7310 to establish a series of priorities for research into the needs of the forestry sector. Specifically, collaborative research efforts into the increased use of CLT in support of the expansion of this portion of the forest products industry were addressed. Cross laminated timber products have been included in updates to national and international building codes, and new production facilities continue to come online. WoodWorks (2019) reports that 105 CLT based construction projects are in construction or completed, and 200 are in the design process. These projects are scattered across the United States, including in the highest areas of decay potential (Figure 1). Mississippi State University Department of Sustainable Bioproducts has several ongoing projects to investigate the durability of CLT under various conditions. These are partnerships with other investigators, primarily with USDA Forest Products Lab personnel, and are housed at both MSU Department of Sustainable Bioproducts facilities in Starkville, MS as well as Forest Products Lab locations in Madison, WI, McNeill, MS, and Saucier, MS. CLT is being tested in several different formats and in test pieces of different sizes. In an ideal situation, CLT panels would be tested at their full size, however, the time it would take to do so, and the logistics of handling pieces of typical size is prohibitive for rapid assessment of the product. Assessments of CLT to date have focused on examining the durability of CLT when exposed to hazards that occur in the high hazard zones of deterioration, such as fungi, termites, and natural weathering. This report describes the collaborative testing of CLT against termite infestation and damage.
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Utility of Image Software in Quantification of Termite Damage on Cross-Laminated Timber (CLT)

https://research.thinkwood.com/en/permalink/catalogue2344
Year of Publication
2019
Topic
Serviceability
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
França, Tamara S.F.A.
Stokes, C. Elizabeth
Tang, Juliet D.
Arango, Rachel A.
Year of Publication
2019
Country of Publication
United States
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Serviceability
Keywords
Termites
Mass Loss
Image Analysis
Language
English
Conference
International Nondestructive Testing and Evaluation of Wood Symposium
Research Status
Complete
Summary
Cross Laminated Timber (CLT) is part of a new generation of engineered wood products that are now widespread across Europe, Australia, and Canada. As this trend is now growing in the United States, manufacturers are looking to expand the use of CLT into the North American market, which includes states located in the southeastern U.S. As this region is known to have an increased risk of termite attack, standards should be developed to evaluate termite damage on CLT products prior to extensive use of the product in this region. However, existing standard test methods cannot be applied directly to CLT specimens as current standard test sample sizes are too small to adequately represent CLT constructed materials. Therefore, larger sample sizes were examined to determine resistance of CLT products against termite attack. Large sample size made it difficult to evaluate termite damage using weight loss as a variable as termite damaged specimens showed relatively low weight loss values. The objective of this work was to examine the use of the image analysis software, ImageJ, in determining the extent of termite damage on CLT blocks. Results showed that evaluation of void volume percent could be used in conjunction with weight loss and visual rating to obtain a more accurate measurement of overall termite damage in CLT.
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Free
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