scholarly journals SHEAR STRENGTH IN THE GLUE LINE OF Eucalyptus sp. AND Pinus sp.WOOD

2016 ◽  
Vol 40 (6) ◽  
pp. 1109-1117
Author(s):  
Juliana Jerásio Bianche ◽  
Angélica de Cássia Oliveira Carneiro ◽  
João Paulo Silva Ladeira ◽  
Ana Paula Mendes Teixeira ◽  
Flávia Alves Pereira ◽  
...  
Keyword(s):  
Shear Strength ◽  
Glue Line ◽  
Chemical Bonds ◽  
Specific Load ◽  
Resorcinol Formaldehyde ◽  
Satisfactory Performance ◽  
Eucalyptus Wood ◽  
Load Tests ◽  
Adhesive Effect ◽  
Glued Joints

ABSTRACT To evaluate the adhesive efficiency on the union of glued joints in a particular temperature and humidity conditions for a specified time the adhesive must be submitted to specific load tests, such as shear in the glue line. The objective of this study was to evaluate the shear strength in the glue line of Eucalyptus sp and Pinus sp.woods. Five adhesives (castor oil, sodium silicate, modified silicate, , PVA and resorcinol-formaldehyde), three weights (150 g/m2, 200 g/m2, and 250 g/m2) and two species (Eucalyptus sp. and Pinus sp.) of wood were used. Twelve specimens were obtained from each repetition per treatment, corresponding to 108 specimens that were conditioned at a temperature of 23 ± 1°C and relative humidity of 50 ± 2%. The interaction between the weight and type of adhesive was significant for the shear strength in the glue line of eucalyptus wood. However, no interaction between the weight and the adhesive was found for pinus, only the isolated from the adhesive effect. Chemical bonds originated in the polymerization of resorcinol-formaldehyde adhesives and castor bi-component conferred upon these adhesives the greatest resistance in the glue line. Castor and resorcinol-formaldehyde adhesives showed the highest shear strength values in the line of glue and wood failure. Castor adhesive presented satisfactory performance for bonding of eucalyptus and pine woods.

Characterizing Star-sawn Pattern–Produced and Orthogonally Glued Specimens of Southern Pine

2019 ◽  
Vol 69 (1) ◽  
pp. 53-60
Author(s):  
Guangmei Cao ◽  
Rubin Shmulsky ◽  
Ming Liu ◽  
Edward D. Entsminger ◽  
Brian K. Via ◽  
...  
Keyword(s):  
Shear Strength ◽  
Dimensional Change ◽  
Good Alternative ◽  
Glue Line ◽  
Wood Failure ◽  
Formaldehyde Resin ◽  
Southern Pine ◽  
Resorcinol Formaldehyde ◽  
Lower Shear ◽  
Pinus Spp

Abstract In this study, triangular specimens of southern pine (Pinus spp.; SP) generated by a star-sawn process were characterized according to knots and deformation. SP specimens were used to understand the differences among glue-line combinations of radial-to-radial, radial-to-tangential, and tangential-to-tangential faces bonded with phenol resorcinol formaldehyde resin. The specimens were tested for shear strength, dimensional stability, wood failure, and delamination rate in accordance with ASTM D1037 and D2559 standards. Among the star-sawn triangular samples studied, bows in tangential-face sections occurred the most. The radial-face sections of SP triangular specimens had more knots but a much lesser degree of deformation than the tangential-face sections. The tangential-to-tangential face glue-line samples showed a lower shear strength, more wood failure, and a greater tendency of delamination and dimensional change, especially when subjected to wet conditions. Confocal microscopic pictures revealed that the tangential-to-tangential glue line showed a greater tendency of deformation in the earlywood part and helped to explain the reason for poor glue-line durability and low shear strength. This article revealed that the star-sawn–process generated wood radial-face samples were more stable than others tested and are perhaps a good alternative for massive panel manufacturing.

scholarly journals Methodology and device to obtain torsional shear strength of glued joints

FLORESTA ◽  
2020 ◽  
Vol 50 (4) ◽  
pp. 1921
Author(s):  
Alfredo Petrauski ◽  
Sandra Maria Ferreira Couri Petrauski ◽  
Ricardo Marius Della Lucia ◽  
Mateus Couri Petrauski
Keyword(s):  
Shear Strength ◽  
Bending Moment ◽  
Wood Adhesive ◽  
Compression Tests ◽  
Resorcinol Formaldehyde ◽  
Mechanics Of Materials ◽  
Significant Difference ◽  
Characterization Procedure ◽  
Wooden Structures ◽  
Glued Joints

This paper presents a methodology to obtain the shear strength of glued joints, at the torsion moment. In the current standards this strength is measured by compression tests. The device designed for this purpose are also presented. The motivation for this test is related to the possibility of execution of glued wooden structures with joints under bending moment, shear force and normal force simultaneously. It was admitted the hypothesis that the joint strength can be different depending on the test type. The methodology is relatively simple and in order to obtain the results classic equations from Mechanics of Materials were used. The strength results of 198 test specimens, tested by standard methodology, were compared, with an equal number of specimens made and tested with the proposed methodology, resulting in 396 tests. 208 specimens were glued with resorcinol-formaldehyde and 188 with castor oil-based adhesive. The wood used was Eucalyptus sp. The specimens were made according to seven series involving gluing with the following angles between the fibers: 0°, 15°, 30°, 45°, 60°, 75° and 90°. Regardless of the adhesive type, there was a significant difference for the strengths presented by the two methods. From the seven angles studied, it was noticed a difference in six of them, except for the 30° series. The compression shear strength was severely affected by the gluing angle, with increasing losses towards higher angles. On the contrary, the strength offered by the joints tested by torsion did not seem affected by the gluing angle.Keywords: wood; adhesive; characterization; procedure.

Influence of anatomy on the adhesion performance of four wood species

2020 ◽  
Vol 9 (4) ◽  
pp. e31942727
Author(s):  
João Gabriel Missia da Silva ◽  
Pedro Nicó de Medeiros ◽  
Denise Ransolin Soranso ◽  
Vinicius Peixoto Tinti ◽  
José Tarcísio da Silva Oliveira ◽  
...  
Keyword(s):  
Shear Strength ◽  
Specific Gravity ◽  
Wood Species ◽  
Tectona Grandis ◽  
Glue Line ◽  
Anatomical Characteristics ◽  
Ray Cells ◽  
Adhesion Performance ◽  
Adhesion Process

The aim of this study was to evaluate the influence of anatomical characteristics on the adhesion performance of Vatairea sp., Paulownia sp., Aspidosperma populifolium and Tectona grandis wood. Specimens for anatomical, physical and mechanical analyzes were produced from tangentially oriented boards. The treatments were joint glued from pieces of the same anatomical orientation (radial and tangential), evaluated for shear strength and glue line failure. The Vatairea sp wood had the highest specific gravity (0.74 g cm-3) and the Paulownia sp (0.34 g cm-3) wood was smaller. Aspidosperma populifolium species showed the highest shear strength in the glue line in the tangential and radial faces. The anatomical variables with higher influence on the wood adhesion process were pith ray cells and especially fibers that exhibit the greatest correlation with the shear strength of the glue line.

Triaxial Characterization of Minnesota Road Research Project Granular Materials

1997 ◽  
Vol 1577 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Navneet Garg ◽  
Marshall R. Thompson
Keyword(s):  
Shear Strength ◽  
Granular Materials ◽  
Resilient Modulus ◽  
Axial Strain ◽  
Confining Pressure ◽  
Engineering Properties ◽  
Shear Tests ◽  
Road Project ◽  
Load Tests ◽  
Repeated Load

Six granular materials were used as base and subbase materials in the flexible pavement test sections for the Minnesota Road Research (Mn/ROAD) project. Crushed/fractured particles are not allowed in aggregate classes CL-1Fsp, CL-1Csp, CL-3sp, and CL-4sp. Ten to 15 percent crushed/fractured particles are required for CL-5sp. One hundred percent crushed/ fractured particles are required for CL-6sp. A comprehensive laboratory testing program was established to determine pertinent engineering properties of the granular materials. Rapid shear tests and repeated-load tests were conducted to determine the shear strength parameters (friction angle and cohesion), resilient modulus, rutting potential, stress history effects on shear strength, and moisture susceptibility. The results from the rapid shear tests and permanent deformation tests show that the rutting potential of a granular material can be characterized from rapid shear test at a confining pressure of 15 psi (103.35 kPa). The rutting parameter A was a function of the shear strength of the granular materials. The shear strength results obtained from rapid shear tests performed at a confining pressure of 15 psi reflect the rutting trends observed in the low-volume road test sections at the Mn/ROAD project. Results from repeated-load tests were used to develop the parameters for K-θ, UT-Austin, and Uzan’s models for evaluating the resilient modulus of granular materials. The axial strain values calculated from the resilient modulus models appear to be in good agreement with the measured axial strain values, except for the very low shear strength material CL-1Csp.

scholarly journals Within-site variability and reliability of foundation designs based on load tests

2019 ◽  
Author(s):  
◽  
Andrew Z. Boeckmann
Keyword(s):  
Load Test ◽  
Test Results ◽  
Considerable Variability ◽  
Specific Load ◽  
Primary Input ◽  
Bayesian Techniques ◽  
Test Information ◽  
Load Tests ◽  
A Site ◽  
Site Variability

Probabilistic evaluations of the reliability of foundation designs based on site-specific load test information are somewhat limited in number. Published evaluations have generally relied on Bayesian techniques. A primary input for Bayesian analysis is within-site variability, which describes the variability of foundation resistance across a site. Within-site variability is attributed to geologic variation across a site and to differences in construction outcomes among foundation elements. Published evaluations have generally used a deterministic value of within-site variability wherein within-site variability is treated as a known parameter and is not subject to updating based on load test results. In contrast, probabilistic within-site variability treats within-site variability as an uncertain parameter with its own probability distribution that is updated based on load test results. Probabilistic within-site variability has not been applied commonly. This research examines differences in reliability outcomes between deterministic and probabilistic within-site variability. Analysis of micropile load test results from five different sites was used to develop a distribution of within-site variability. The resulting distribution is relatively variable (i.e. the value of within-site variability is, itself, variable), which demonstrates that there is, in fact, considerable variability and uncertainty in the value of within-site variability.

scholarly journals EFFECT OF THE HEAT TREATMENT OF Hovenia dulcis Thunb. WOOD ON THE PRODUCTION OF EGP PANELS WITH DIFFERENT ADHESIVES

FLORESTA ◽  
2020 ◽  
Vol 50 (4) ◽  
pp. 1761
Author(s):  
Raquel Marchesan ◽  
Edison Toledo Corrêa dos Santos ◽  
Rosilani Trianoski ◽  
Morgana Cristina França ◽  
Pedro Licio Loiola ◽  
...  
Keyword(s):  
Shear Strength ◽  
Urea Formaldehyde ◽  
External Environment ◽  
Treated Wood ◽  
Polymer Emulsion ◽  
Resorcinol Formaldehyde ◽  
Minimum Standards ◽  
Heat Treated ◽  
Pre Treatment ◽  
Hovenia Dulcis

The objective of this work was to analyze the shear strength of edge-glued panels (EGP) made from the H. dulcis Thunb. wood thermally modified by the VAP HolzSysteme® process. Initially, the Hovenia dulcis samples were heat-annealed by the VAP HolzSysteme® process, and then bonded with Resorcinol-formaldehyde (RF), Melamine-urea-formaldehyde (MUF), Isocyanate Polymer Emulsion (EPI) and Polyvinylacetate (PVAc) and submited to pre-treatments for dry, humid and external environment and without pre-treatment to evaluate the shear strength, 5th percentile and failure in the wood. It was observed a decrease in the shear strength of the thermorrectified H. dulcis wood for all adhesives. All adhesives obtained results superior to the minimum required by the standard EN13354 (2009) for the wood without pre-treatment as for the wood without thermoregulation as well as for the heat treated wood, and may be used for non-structural purposes. However, for the external environment (three cycles) only the MUF adhesive obtained value that meets the minimum standards of the standard, in this way, it is suggested to glue the EGP of H. dulcis without thermortification and with thermorrectification using the MUF adhesive, which has achieved better performance offering greater resistance in dry, wet and external environments.

scholarly journals THE USE OF Eucalyptus camaldulensis AND Eucalyptus urophylla WOOD IN THE PRODUCTION OF EDGE GLUED PANELS

FLORESTA ◽  
2019 ◽  
Vol 49 (2) ◽  
pp. 317 ◽  
Author(s):  
Setsuo Iwakiri ◽  
Rosilani Trianoski ◽  
Angela Stüpp ◽  
Bruna Mulinari Cabral ◽  
Jéssika Alvares Coppi Arruda Gayer
Keyword(s):  
Shear Strength ◽  
Eucalyptus Camaldulensis ◽  
Glue Line ◽  
Eucalyptus Urophylla ◽  
Shear Tests ◽  
Minimum Requirement ◽  
Dry And Wet Conditions ◽  
Lower Percentile

This study aimed to evaluate the shear strength of bonded wood joints of Eucalyptus camaldulensis and Eucalyptus urophylla with vinyl polyacetate (PVA) and isocianate polymeric emulsion (EPI) adhesives with the amount of glue of 150 and 180 g/m². The specimens were submitted to shear tests in dry and wet conditions, based on the procedure described in standard EN 13354 (2008). The results of the 5th lower percentile were compared with the requirements of EN 13353 (2008). Among the studied species, Eucalyptus camaldulensis showed better glue line shear strength when compared to Eucalyptus urophylla. However, both species are potentially viable for the edge glued panel (EGP) production, since they meet the minimum requirement of 2.5 MPa, referring to the 5th lower percentile, as established by EN 13353-2008 standard. Based on the results, it is recommended the use of EPI adhesive with the amount of glue of 150 g/m² for the bonding of the wood of these species, aiming at the production of EGP. 

scholarly journals ANALYSIS OF EUCALYPTUS GLUED-LAMINATED TIMBER PORTICOS STRUCTURAL PERFORMANCE

2016 ◽  
Vol 40 (5) ◽  
pp. 931-939 ◽  
Author(s):  
Sandra Maria Ferreira Couri Petrauski ◽  
José de Castro Silva ◽  
Alfredo Petrauski ◽  
Ricardo Marius Della Lucia
Keyword(s):  
Mechanical Performance ◽  
Structural Performance ◽  
Load Testing ◽  
Bonding Pressure ◽  
Resorcinol Formaldehyde ◽  
Average Value ◽  
Design Load ◽  
Glued Laminated Timber ◽  
Real Scale ◽  
Glued Joints

ABSTRACT This study evaluated the structural behavior of porticos made from eucalyptus glued boards, using wood of Eucalyptus sp and resorcinol formaldehyde adhesive. Three units, in real scale, of tri-articulated straight porticos, with a 5 meter porthole and a 26º inclination, capable to support tiles covering placement were designed, constructed and subjected to load testing, until rupture. The amount of adhesive used in the construction of the porticos was 250 g/m2 and the bonding pressure of 1.3 MPa. The Hankinson model was employed as an estimator of the glued joints strength, under different angles between the fibers. The average value for the last resistance of the structures was 4.63 times the design load, according to the criteria established by the ABNT, 1997. The structures showed satisfactory mechanical performance and deformations lower than the ones allowed by the standard. It was concluded there is technical feasibility to manufacture porticos fully bonded with small thickness veneers.

scholarly journals Mechanical tests on Corymbia citriodora battenboard panels coated and reinforced with giant bamboo veneers

2019 ◽  
Vol 49 ◽  
Author(s):  
Fabiano Ostapiv
Keyword(s):  
Mechanical Tests ◽  
Glue Line ◽  
Mechanical Resistance ◽  
Mechanical Reinforcement ◽  
Bending Tests ◽  
Laminated Bamboo ◽  
Eucalyptus Wood ◽  
Tensile Forces ◽  
Bamboo Fibers ◽  
Corymbia Citriodora

ABSTRACT Dense wood batten panels usually break in the glue line when loaded. This study demonstrates that thin veneers obtained from mature culms of Dendrocalamus asper by mechanical grinding are suitable for coating and reinforcing solid processed eucalyptus wood and eucalyptus batten panels. Tensile and bending tests were carried out on Corymbia citriodora timber and edge glued batten panels, with and without bamboo veneer reinforcement. The tensile test results showed that the bamboo veneers glued onto the wood and edge glued batten panels specimens acted as a mechanical reinforcement for both cases, when submitted to tensile forces parallel to the bamboo fibers. In bending tests, the edge glued batten panels specimens were tested transversally to the glue line, direction in which the panel showed the lowest mechanical resistance. The edge glued batten panels specimens without reinforcement with laminated bamboo exhibited a fragile behavior and ruptured abruptly along the glue line. A significant increase in the mechanical strength of the set was observed for the edge glued batten panels coated with laminated bamboo. In addition, the mechanical behavior changed in reinforced specimens, which ruptured slowly and gradually in the bending tests.

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