scholarly journals Gluing Techniques on Bond Performance and Mechanical Properties of Cross-Laminated Timber (CLT) Made from Larix kaempferi

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 733
Author(s):  
Mingyue Li ◽  
Shuangbao Zhang ◽  
Yingchun Gong ◽  
Zhaopeng Tian ◽  
Haiqing Ren
Keyword(s):  
Surface Treatment ◽  
Raw Material ◽  
Bonding Layer ◽  
Larix Kaempferi ◽  
Bonding Pressure ◽  
Bonding Quality ◽  
Cross Laminated Timber ◽  
Bond Performance ◽  
Block Shear ◽  
Shear Performance

Previous studies have proved that Larix kaempferi is a good material for preparing cross-laminated timber (CLT), but under bending shear stress, CLT made by Larix kaempferi is prone to the phenomenon of bonding face cracking, which seriously affects the shear performance of CLT. To solve this problem, this paper took Larix kaempferi as raw material, conducted experiments on the surface sanding conditions, gluing pressure and adhesive types of sawing timber, and explored the influence of these three factors on the bonding quality of CLT. The microscopic characteristics of the bonding layer were further studied. The results showed that for Larix kaempferi with a density of 0.68 g/cm3 used in this experiment, a high bonding pressure is required. Among the three cold curing adhesives selected in the experiment, emulsion polymer isocyanate (EPI) adhesive needs 1.5 MPa bonding pressure to ensure the bonding quality, while for polyurethane (PUR) and phenol resorcinol formaldehyde (PRF), 1.2 MPa can meet the need of adhesive pressure. This is concerned with the permeability of different adhesives under different pressures. The microscopic results of the bonding layer show that EPI adhesives have poor permeability, so it requires high bonding pressure. The influence of sanding surface of different sand-belt on block shear strength (BSS) and wood failure percentage (WFP) is not obvious, while the durability of bonding layer is better when sanding mesh number is 100. Hence, a high pressure should be used for CLT industrial production when the laminate density is higher, especially when the adhesive has poor permeability. Reasonable sanding surface treatment can be used in laminate surface treatment to improve the durability of CLT.

scholarly journals Early-Age Tensile Bond Characteristics of Epoxy Coatings for Underwater Applications

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 757 ◽  
Author(s):  
Kim ◽  
Hong ◽  
Han ◽  
Kim
Keyword(s):  
Bond Strength ◽  
Surface Treatment ◽  
Epoxy Resin ◽  
Coating Thickness ◽  
Experimental Results ◽  
Early Age ◽  
Curing Time ◽  
Bond Performance ◽  
Coating Type ◽  
Bond Characteristics

In this study, coating equipment for the effective underwater repair of submerged structures was developed. The tensile bond characteristics of selected epoxy resin coatings were investigated by coating the surface of a specimen using each of the four types of equipment. Using the experimental results, the tensile bond strength and the coating thickness were analyzed according to the type of equipment, coating, and curing time. The results show that the type of coating equipment used had the greatest effect on the measured bond strength and coating thickness of the selected coatings. However, the effect of coating type and curing time on the bond strength and the thickness was observed to be insignificant. Compared with the developed equipment, the surface treatment of the coating was observed to be more effective when using the pre-existing equipment, and thus the bond performance of the coating was improved compared to using the pre-existing equipment. Based on the experimental results, improvements and needs involving the equipment for further research were discussed.

scholarly journals Withdrawal Properties of Self-Tapping Screws in Japanese larch (Larix kaempferi (Lamb.) Carr.) Cross Laminated Timber

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 524
Author(s):  
Junhua Xu ◽  
Shuangbao Zhang ◽  
Guofang Wu ◽  
Yingchun Gong ◽  
Haiqing Ren
Keyword(s):  
Regression Model ◽  
Engineering Design ◽  
Wood Species ◽  
Japanese Larch ◽  
Effective Length ◽  
Larix Kaempferi ◽  
Cross Laminated Timber ◽  
The World ◽  
Different Types ◽  
Length Increment

With the increasing popularity of cross-laminated timber (CLT) constructions around the world, there have been attempts to produce CLT using local wood species in different countries, such as Japanese larch (Larix kaempferi (Lamb.) Carr.) in China. Thus, the need to investigate the connection performance also increases to support the design and construction of CLT buildings using local wood species. In this study, the withdrawal properties of three different types of self-tapping screws (STS), with a diameter of 6 mm, 8 mm, and 11 mm, were tested with Japanese larch CLT. The results revealed that the withdrawal strength of STS increased with increasing density and effective length, but decreased with an increasing diameter. With a density increment of 0.05 g/cm3, the withdrawal strength increased by an average of 9.4%. With an effective length increment of 24 mm, the withdrawal strength increased by an average of 1.4%. An empirical regression model was adopted to predict the withdrawal strength of Japanese larch CLT based on the results, which can be used for potential engineering design of CLT connections using STS.

scholarly journals PULL-OUT RESISTANCE OF SELF-TAPPING SCREWS IN CROSS-LAMINATED TIMBER MADE FROM RADIATA PINE

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Xin Li ◽  
Mahmud Ashraf ◽  
Mahbube Subhani ◽  
Paul Kremer
Keyword(s):  
Failure Modes ◽  
Construction Materials ◽  
Structural Response ◽  
Radiata Pine ◽  
Raw Material ◽  
Fibrous Materials ◽  
Cross Laminated Timber ◽  
Pull Out ◽  
Traditional Construction ◽  
Penetration Depths

Cross-laminated timber (CLT) is now considered a viable alternative to traditional construction materials both in mid-rise and high-rise structures. The structural response of CLT heavily relies on the type of timber used in manufacturing, and this can vary significantly based on the original source for this naturally grown raw material. Spruce has been widely used in Europe for CLT production, but in Australia, locally available radiata pine is used by XLam for the manufacturing of their CLT panels. Self-tapping screws (STS) are typically recommended by CLT manufacturers and are most commonly used in relevant construction due to their high load carrying capacities and easy installation process. VGS STSs produced by Rothoblaas were used to investigate their composite actions when pulled-out from three-layer XLam CLT panels with thicknesses of 105 mm and 135 mm. VGS screws with 11 mm in diameter were inserted both parallel-to-grain and perpendicular-to-grain on the narrow face of the CLT panels as part of the current study. Typical failure modes as well as critical penetration depths were carefully recorded. Obtained results showed significant increase of pull-out capacity as penetration depths were increased for considered cases. However, experimental results also showed some obvious inconsistencies. These observations clearly demonstrate the challenges associated with working naturally grown fibrous materials and highlights the importance of major research on this field.

scholarly journals Long-term bending properties of cross-laminated timber made from Japanese larch under constant environment

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Ryuya Takanashi ◽  
Yoshinori Ohashi ◽  
Wataru Ishihara ◽  
Kazushige Matsumoto
Keyword(s):  
Load Capacity ◽  
Creep Rupture ◽  
Japanese Larch ◽  
Larix Kaempferi ◽  
Loading Capacity ◽  
Loading Test ◽  
Cross Laminated Timber ◽  
Duration Of Load ◽  
Rupture Behavior

AbstractCross-laminated timber (CLT) has been used extensively in timber construction. CLT panels are typically used in roofs and floors that carry a continuous load, and it is important to examine the long-term loading capacity of CLT. However, studies that focus on the long-term loading capacity of CLT are limited. To this end, we conducted long-term out-of-plane bending tests on seven-layer CLT made from Japanese larch (Larix kaempferi) under constant environmental conditions, investigated creep performance and duration of load, and experimentally analyzed creep rupture behavior. The mean estimated relative creep after 50 years was 1.49. The sample showed a satisfactory resistance to creep as a building material. The duration of load of most of the specimens in this study was shorter than the conventional value of small clear wood specimens. Specimens had a lower duration of load capacity than solid lumber. According to the results of survival analysis, a loading level of 70% or more caused the initial failure of specimens. Creep rupture of most of the specimens occurred at less deflection than displacement at failure in the short-term loading test. Additional studies focusing on the effects of finger joints, transverse layers, and width of a specimen on creep rupture behavior are suggested.

Bonding quality of cross-laminated timber: Evaluation of test methods on Eucalyptus grandis panels

2019 ◽  
Vol 211 ◽  
pp. 217-227 ◽  
Author(s):  
Michael Dugmore ◽  
Michela Nocetti ◽  
Michele Brunetti ◽  
Zahra Naghizadeh ◽  
C. Brand Wessels
Keyword(s):  
Eucalyptus Grandis ◽  
Test Methods ◽  
Bonding Quality ◽  
Cross Laminated Timber

scholarly journals Investigation and Characterization of Synthesis Conditions on Sucrose-ammonium Dihydrogen Phosphate (SADP) Adhesive: Bond Performance and Chemical Transformation

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4078 ◽  
Author(s):  
Shijing Sun ◽  
Min Zhang ◽  
Kenji Umemura ◽  
Zhongyuan Zhao
Keyword(s):  
Chemical Analysis ◽  
Chemical Transformation ◽  
Raw Material ◽  
Synthesis Process ◽  
Dihydrogen Phosphate ◽  
Ammonium Dihydrogen Phosphate ◽  
Synthesis Time ◽  
Synthesis Conditions ◽  
Renewable Chemicals ◽  
Bond Performance

Sucrose is one of the most abundantly available renewable chemicals in the world, and it is expected to be utilized as a raw material for wood-based material products. Herein, a novel adhesion system that was based on sucrose and ammonium dihydrogen phosphate (ADP) was synthesized into an adhesive with 80% solid content, and this eco-friendly was utilized on the fabrication of plywood. The effects of the synthesis conditions on the plywood bond performance and synthesis mechanism were investigated. The optimal synthesis conditions were as follows: the mass proportion between sucrose and ADP was 90/10, the synthesis temperature was 90 °C, and the synthesis time was 3 h. The bonding performance of the plywood that was bonded by optimal SADP adhesive satisfied the GB/T 9846-2015 standard. The chemical analysis was performance tested by using High-Performance Liquid Chromatography (HPLC), Attenuated Total Reflection-Fourier Transform Infrared Spectra (ATR-FTIR), and Pyrolysis Gas Chromatography and Mass Spectrometry (Py-GC/MS) to understand the chemical transformation during the synthesis process. The chemical analysis results confirmed that the hydrolysis and conversation reaction of sucrose occurred in the synthesized SADP adhesive, and ADP promoted the pyrolysis efficiency of sucrose.

Manufacturing Issues and Considerations in Thermal Bonding of Polymer Based Lab-on-a-Chip

2009 ◽  
Vol 74 ◽  
pp. 175-178
Author(s):  
Yu Xin Koh ◽  
Sum Huan Ng ◽  
Khin Thet May ◽  
Cong Zhi Chan ◽  
Zhi Ping Wang
Keyword(s):  
Bond Strength ◽  
Surface Topography ◽  
Lab On A Chip ◽  
Microfluidic Devices ◽  
Thermal Bonding ◽  
Bonding Pressure ◽  
Bonding Quality ◽  
Viscoelastic Effect ◽  
Common Technique

The sealing of microchannels is a key step in the fabrication of microfluidic devices and thermal bonding is a common technique used. Here, major manufacturing issues and considerations in thermal bonding are investigated, including bonding quality and microchannel deformations. Flatness of substrate is extremely crucial to the uniformity in bonding. While increased bonding pressure helps to overcome problems related to surface topography and to enhance bond strength, its significant impact on geometrical changes of microchannel due to viscoelastic effect should also be taken into consideration.

scholarly journals The influence of the opening size on the shear performance of the cross-laminated timber (CLT) walls

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 7071-7085
Author(s):  
Daiyuan Zhang ◽  
Liming Shen ◽  
Xudong Zhu ◽  
Sujun Zhang ◽  
Meng Gong
Keyword(s):  
Shear Strength ◽  
Mechanical Performance ◽  
Shear Stiffness ◽  
High Strength ◽  
Load Test ◽  
Static Load Test ◽  
Cross Laminated Timber ◽  
Wall Panels ◽  
Shear Performance ◽  
The Cross

Cross-laminated timber is a wood product with excellent fire resistance and mechanical performance that is often used in tiny houses. Using the ASTM standard E564, the shear performance of cross-laminated timber wall panels, with and without openings, were investigated in this study. The specimens were made of spruce-pine-fir IIc lumber and installed on a test platform using high-strength bolts passing through them. This connection mode limited the displacements obtained in the test, primarily the shear displacements and rocking displacements. By comparing the static load test data of the three specimens with openings and the one without an opening, it was found that openings reduced the shear strength and shear stiffness. For the same sized rectangular opening, the shear stiffness of the cross-laminated timber panel was less when the wider side was horizontal (normal to the direction of the applied force). The shear stiffness of the cross-laminated timber wall panels can be effectively improved by reinforcing the areas near the openings with metal sheets. With reinforcement, the shear strength did not change drastically, but the damage to the cross-laminated timber wall panels was significantly reduced.

Sign in / Sign up

Export Citation Format

Share Document