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42 records – page 1 of 5.

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
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
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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Development Of CLT Products with Improved Fire Performance

https://research.thinkwood.com/en/permalink/catalogue2598
Year of Publication
2020
Topic
Design and Systems
Fire
Material
CLT (Cross-Laminated Timber)
Author
He, Guangbo
Feng, Martin
Roussiere, Fabrice
Organization
FPInnovations
Year of Publication
2020
Format
Report
Material
CLT (Cross-Laminated Timber)
Topic
Design and Systems
Fire
Keywords
Fire Resistance
Adhesives
Bond Durability
Bonding
Treated Wood
Research Status
Complete
Summary
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.
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Fire Performance of Cross-Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue2227
Year of Publication
2019
Topic
Fire
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Olivier, Gerhard
Organization
Delft University of Technology
Year of Publication
2019
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Fire
Keywords
Small Scale
Adhesives
Fire Behaviour
Compartment Fire Test
Self-Extinguishment
Research Status
Complete
Summary
Cross-Laminated timber (CLT), and other engineered timber products, are under high demand due to their prefabricated nature and environmental benefits. A key concern surrounding the application of CLT in buildings is its combustible nature and subsequent contribution to a compartment fire. Previous research has shown that exposed CLT, under certain circumstances, can achieve self-extinguishment. This research aims to further experimentally investigate the fire performance of small-scale compartments containing exposed CLT. The focus of this study is threefold, namely to investigate: i) the influence of (commercially available) adhesives used in CLT panels on fire behaviour; ii) the influence of CLT panel configuration on fire behaviour and iii) the ability of design guidelines to predict experimentally obtained fire behaviour. By investigating these aspects, a detailed investigation into fire behaviour of compartments with exposed CLT is presented to characterise the influence of CLT on enclosure fire behaviour and assess the ability of CLT to reliably self-extinguish. In general, it was found that reliable self-extinguishment is promoted when small-scale compartment fire tests reveal the avoidance of burn-through behaviour (and a second flashover), due to the combined effect of CLT adhesive type and CLT panel configuration. The particular observations recorded in this research project (relating to adhesive type and CLT panel configuration) serve as a base on which to conduct further research (especially by conducting experiments at real compartment scales). In addition, the investigation into the ability of a design guideline to predict fire behaviour, namely a Parametric Fire Curve (PFC) calculation method that includes the contribution of exposed CLT to the fuel load, provided mixed results. Further refinement is required to improve the model’s ability to predict compartment behaviour.
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Structural Performance Analysis of Cross-Laminated Timber-Bamboo (CLTB)

https://research.thinkwood.com/en/permalink/catalogue2415
Year of Publication
2019
Topic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Other Materials
Application
Floors
Walls
Wood Building Systems
Author
Barreto, Maria Izabel de Mello
Almeida De Araujo, Victor
Cortez-Barbosa, Juliana
Christoforo, Andre Luis
Moura, Jorge Daniel de Melo
Organization
State University of Londrina
Federal University of São Carlos
Publisher
North Carolina State University
Year of Publication
2019
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Other Materials
Application
Floors
Walls
Wood Building Systems
Topic
Design and Systems
Keywords
Adhesives
Bamboo
Lignocellulosic Material
Wood-Bamboo Construction
Structural Panels
Research Status
Complete
Series
BioResources
Summary
Construction systems based on cross-laminated timber (CLT) have versatility in material development and are an interesting alternative for construction. This study evaluated the structural performance of cross-laminated timber-bamboo produced from wood (Pinus spp.) and bamboo (Dendrocalamus giganteus). Panels were produced by strips (wood and bamboo) assorted, under non-destructive structural grading, to support a better panel configuration. Small-length pine pieces were also included in the study, considering their low added-value and underutilization in sawmills from Telêmaco Borba, Brazil. Gluing tests of small specimens were performed to evaluate the bonding quality of three adhesives: melamine-urea-formaldehyde (MUF), isocyanate polymeric emulsion (IPE), and castor oil-based resin (COR). Shear stress strength parallel to grain between bamboo and wood showed the best performance for MUF resin. After preliminary gluing testing, eight cross-laminated panels were produced with MUF adhesive in a three-layered configuration, with transversal orientation: two external bamboo layers and a central layer of pine wood. Stiffness and rupture strength values were above those specified by the ANSI/APA PGR 320 (2012) standard. Elasticity and rupture moduli were 13,310 MPa and 65 MPa, respectively, showing good potential of this composite for structural uses.
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Mechanical Properties of Cross-laminated Timber (CLT) Panels Composed of Treated Dimensional Lumber

https://research.thinkwood.com/en/permalink/catalogue2423
Year of Publication
2019
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Walls
Floors
Author
Tripathi, Sachin
Publisher
Mississippi State University
Year of Publication
2019
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Walls
Floors
Topic
Mechanical Properties
Keywords
Panels
Rolling Shear
Preservative
Adhesives
Southern Yellow Pine
Out-of-Plane Load
Research Status
Complete
Summary
This research study investigates the effect of micronized copper azole type C (MCA-C) preservative system on the rolling shear (RS) properties of CLT. In the first part of research, bonding performance of CLT panels treated at two retention levels, 0.96 kg/m3 and 2.5 kg/m3, were evaluated. Three structural adhesive systems, melamine formaldehyde (MF), resorcinol formaldehyde (RF) and one-component polyurethane (1C-PUR) were used to assemble visually graded No. 2 2×6 southern yellow pine (SYP) lumber while manufacturing CLT panels. For treated CLT panels, 1C-PUR provides better bonding performance test results. The RS properties of MCA-C treated CLT panels were studied in the second part of the research. The CLT panels were subjected to out-of-plane loading according to the EN 16351 standard. The mean values of RS strength and modulus of treated CLT were 1.89 MPa and 289.4 MPa respectively.
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Use of Northern Hardwoods in Glued-laminated Timber: A Study of Bondline Shear Strength and Resistance to Moisture

https://research.thinkwood.com/en/permalink/catalogue2427
Year of Publication
2019
Topic
Moisture
Design and Systems
Material
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Author
Achim, Alexis
Blanchet, Pierre
Dagenais, Christian
Morin-Bernard, Alexandre
Organization
Laval University
Year of Publication
2019
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Topic
Moisture
Design and Systems
Keywords
Adhesives
Engineered Wood Product (EWP)
Hardwood
Shear Strength
Failure
Wet Conditions
Conference
International Scientific Conference on Hardwood Processing
Research Status
Complete
Summary
The growing demand for engineered wood products in the construction sector has resulted in the diversification of the product offer. Used marginally in structural products in North America, northern hardwoods are now attracting a growing interest from industry and policy makers because of their outstanding strength as well as their high availability and distinctive appearance. Currently, there is no standard in Canada governing the use of hardwoods in the manufacturing of glued-laminated timber. As part of a larger project aiming to assemble the basic knowledge that would lead to such standard, the specific objective of this study was to assess the shear strength in dry and wet conditions of assemblies made from different hardwood species and structural adhesives. Results suggest that a mean shear strength as high as 20.5 MPa for white oak, 18.8 MPa for white ash and respectively 18.2 MPa and 17.4 MPa for yellow birch and paper birch can be obtained in dry conditions. The choice of adhesive did not affect the dry shear strength of our specimens, but differences were observed in wet conditions. Specimens bonded with melamine-formaldehyde adhesive had generally the highest wet shear strength and wood failure values. Our results also highlight the important influence of wood density on the percentage of failure that occurs in wood and, to a lesser extent, on shear strength. Further investigations on finger joint strength and full-size bending tests will allow confirming the potential for the investigated species to be used in glued-laminated timber.
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Influence of Strand Size, Board Density, and Adhesive Type on Characteristics of Oriented Strand Lumber Boards Manufactured from Pine Strands

https://research.thinkwood.com/en/permalink/catalogue2511
Year of Publication
2019
Topic
Design and Systems
Mechanical Properties
Material
OSL (Oriented Strand Lumber)
Application
Beams
Author
Mirski, Radoslaw
Derkowski, Adam
Dziurka, Dorota
Organization
Poznan University of Life Sciences
Publisher
North Carolina State University
Year of Publication
2019
Format
Journal Article
Material
OSL (Oriented Strand Lumber)
Application
Beams
Topic
Design and Systems
Mechanical Properties
Keywords
Pine
Adhesives
MUF
Physical Properties
Bending Test
Tensile Strength
pMDI
Research Status
Complete
Series
BioResources
Summary
The influence of selected technological aspects was studied relative to characteristics of oriented strand lumber (OSL) boards manufactured from pine strands. Six types of boards were prepared, differing in the strand fraction size, density (700 kg/m3 and 800 kg/m3), and adhesive used to glue the strands in the core layer. The adhesives compared were melamine-urea-formaldehyde (MUF) and polymeric diphenylmethane diisocyanate (pMDI). The results showed that the OSL boards had good physical and mechanical properties, even though pine strands of diverse characteristics, particularly in terms of their length and width, were used for their production. The influence of strand size was clear in the results of the bending and elongation tests. Both for the bending test and tensile strength in a direction parallel to the wood grain, the properties were on average 20% greater for boards made of larger strands compared to those made of smaller strands. However, the latter demonstrated greater internal bonding strength (IB). The weakness of OSL boards made from small strands was their low modulus of elasticity, particularly when the board density was simultaneously reduced.
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Development of Adhesive Free Engineered Wood Products - Towards Adhesive Free Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue2029
Year of Publication
2018
Topic
Connections
Design and Systems
Environmental Impact
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Author
Guan, Zhongwei
Sotayo, Adeayo
Oudjene, Marc
el Houjeyri, Imane
Harte, Annette
Mehra, Sameer
Haller, Peer
Namari, Siavash
Makradi, Ahmed
Belouettar, Salim
Deneufbourg, Franscois
Year of Publication
2018
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Topic
Connections
Design and Systems
Environmental Impact
Mechanical Properties
Keywords
Adhesives
Manufacturing
Compressed Wood
Four Point Bending Test
Numerical Models
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
Over 5 million m 3 of engineered wood products (EWPs) are produced in the EU annually and the market is rising. However, EWPs have a high degree of petrochemical use in their manufacturing. In addition, throughout the life span of these EWP products from manufacture to disposal, they emit formaldehyde and other volatile organic compounds (VOCs), which makes recycling very difficult. In this paper, preliminary experimental work on Adhesive Free Engineered Wood Products (AFEWPs) is presented, which covers (1) manufacture of compressed wood (CW) dowels, (2) fabrication of adhesive free laminated beams and connections, (3) structural testing of AFEWPs. Also, the finite element models are being developed to assist designing of AFEWPs in terms of size of compressed wood dowel and dowel patterns in order to maximise their stiffness and load carrying capacities.
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Fire Safety Challenges of Tall Wood Buildings - Phase 2: Task 5 – Experimental Study of Delamination of Cross Laminated Timber (CLT) in Fire

https://research.thinkwood.com/en/permalink/catalogue1211
Year of Publication
2018
Topic
Fire
Connections
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Brandon, Daniel
Dagenais, Christian
Publisher
Fire Protection Research Foundation
Year of Publication
2018
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Fire
Connections
Keywords
Delamination
Adhesives
Compartment Fires
Tall Wood
Research Status
Complete
Summary
Recent architectural trends include the design and construction of increasingly tall buildings with structural components comprised of engineered wood referred to by names including; cross laminated timber (CLT), laminated veneer lumber (LVL), or glued laminated timber (Glulam). These buildings are cited for their advantages in sustainability resulting from the use of wood as a renewable construction material. Previous research has shown that timber elements contribute to the fuel load in buildings and can increase the initial fire growth rate – potentially overwhelming fire protection system and creating more severe conditions for occupants, emergency responders, and nearby properties. The overarching goal of this project Fire Safety Challenges of Tall Wood Buildings Phase 2 (involving five tasks) is to quantify the contribution of CLT building elements (wall and/or floor-ceiling assemblies) in compartment fires and provide data to allow comparison of the performance of CLT systems against other building systems commonly used in tall buildings.
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Experimental Investigation of Flexural Behavior of Glulam Beams Reinforced with Different Bonding Surface Materials

https://research.thinkwood.com/en/permalink/catalogue1312
Year of Publication
2018
Topic
Mechanical Properties
Connections
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Uzel, Murat
Togay, Abdullah
Anil, Özgür
Sögütlü, Cevdet
Publisher
ScienceDirect
Year of Publication
2018
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Connections
Keywords
Epoxy
Polyurethane
Adhesives
Load-Displacement
Ultimate Load Capacity
Ductility
Stiffness
Energy Dissipation
Failure Mechanisms
Research Status
Complete
Series
Construction and Building Materials
Summary
In this study, flexuralbehaviors of glue laminated timber beams manufactured from Pinussylvestristree were investigated by comparing the results with those of massive timber beams. The main variables considered in the study were number of laminations, types of adhesive materials and reinforcement nets used in the lamination surfaces. In scope of the experimental study, glue laminated beams with 5 and 3 lamination layers were manufactured with 90 x 90 mm beam sections. In the lamination process epoxy and polyurethane glue were used. Morever, in order to improve the bond strength at the lamination surface, aluminium, fiberglass and steel wire nets were used at the lamination surfaces. Load–displacement responses, ultimate capacities, ductility ratios, initial stiffness, energy dissipation capacities and failure mechanisms of glue laminated beams were compared with those of massive beams. It was observed that the general bending responses of glue laminated beams were better than those of massive beams. In addition to that the use of reinforcement nets at the lamination surfaces increased the ultimate load capacities of the tested beams. The highest ultimate load capacities were oberved from the tests of glue laminated beams manufactured using five laminated layers and retrofitted with polyurethane glue using steel wire reinforcement nets, in the direction normal to the lamination surface. Finally, the finite element simulations of some test specimens were performed to observe the accuracy of finite element technology in the estimation of ultimate capacities of glue laminated timber beams.
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42 records – page 1 of 5.