Shear Strength of Scots Pine Wood and Glued Joints in a Cold Climate

Abstract

The impact of cold temperatures on the shear strength of Scots pine (Pinus sylvestris) joints glued with seven commercially available adhesives was studied in this work. The cold temperatures investigated were: 20, −20, −30, −40, and −50 °C. Generally, within the temperature test range, the shear strength of Scots pine solid wood and wood joints were more resistant to the effect of temperature than those of Norway spruce. As the temperature decreased, only some of the joints' shear strength significantly decreased. In most cases, PUR adhesive yielded the strongest shear strength and MUF adhesive yielded the weakest shear strength. MF adhesive responded to temperature changes in a similar manner to that of PUR and PVAc adhesives. The shear strengths of wood joints with PRF and EPI adhesives were more sensitive to temperature change. For dynamic tests of shear strength, the values for 12-h and 6-day tests under temperature cycles (−20 and 0 °C) were compared. The values for 6-day tests were lower than those for 12-h tests. Therefore, the duration of the samples subjected to the same temperature had a significant impact on shear strength. Our results indicate that PUR adhesive is the most stable; whereas the stability of MUF and PRF adhesives decreased significantly.

Determining the effect of synthetic-based varnish and impregnation on wood’s shear strength under cold climate conditions

“…In these cases, the design must compensate for the different movements of components while maintaining structural integrity. Good performance of glue lines at high temperatures has been documented (Frangi et al 2004;Falkner and Teutsch 2006;Clauss et al 2011;Wang et al 2016). However, although some studies of wooden bridges in cold climates have been reported, there is not much information about the stability of glue lines at low temperatures, especially extreme cold temperatures (Kainz and Ritter 1998;Wacker 2003Wacker , 2009.…”

“…Wood construction in these areas is frequently exposed to low temperatures for long periods of the year. However, thermal conditions are often not taken into account in the design and estimation of the service life of wood constructions (Wang et al 2016).…”

“…There have been some studies, albeit few, conducted on the effect of sub-zero temperature on the mechanical properties of wood material. Wang et al (2016) tested the experiment samples made of Norway spruce (Picea abies) wood, which they combined with polyurethane (PUR), polyvinyl acetate (PVAc), emulsion-polymer-isocyanate (EPI), melamine-formaldehyde (MF), phenol-resorcinol-formaldehyde (PRF), melamine-urea-formaldehyde1 (MUF1), and melamine-urea-formaldehyde2 (MUF2) glues, in six different temperature environments (20, -20, -30, -40, -50, and -60 °C). In general, temperature changes have significantly affected the glue shear strength.…”

The Influence of Freezing and Thawing Process on the Bending Moment Capacity of L-Shaped Heat-Treated Wood Dowel Joints

“…However, there is a lack of studies regarding the influence of the freezing and thawing process on the strength of heat-treated wood dowel joints. This process can affect the mechanical properties of the joints due to the micro-cracks that occur in the cell wall structure during the freezing process and in the adhesive film as well [16][17].…”

Investigation of Shear Strength of Engineered Wood Flooring Bonded with PUR by Response Surface Methodology

“…The shear strengths of the glue lines declined gradually through testing with polyvinyl acetate (PVA) and MUF/UF adhesives, but the performance of the PUR adhesive was constant. Wang et al (2016) evaluated the shear strength of Scots pine wood and its glued joints in a cold climate with various adhesives. They concluded that as the temperature decreased from 20 °C to -50 °C, the shear strength of the tested PUR bond lines decreased by only 5.8%.…”