The Impacts of Heat Treatment on Lap Joint Shear Strength of Black Pine Wood

Abstract

This study was conducted to determine the impacts of heat treatment on lap shear strength, density, and mass loss of black pine wood. In the study, black pine wood boards bonded with polyurethane were subjected to temperatures of 160, 180, and 200°C for durations of 2 and 6 hours. Specimens having two layers were prepared from untreated and treated wood for mechanical testing of bond lines. Data were analyzed using variance analysis and Tukey's test to determine the impacts of changes in density and mass of heat-treated black pine wood on lap shear strength. The results indicated that the lap shear strength of black pine wood decreased as the intensity of heat treatment increased. The results also indicated that the minimum and maximum percentage decreases of lap shear strength were approximately 27% for 160°C and 2 hours and 78% for 200°C and 6 hours.

Keywords:

• Black pine
• Density loss
• Heat treatment
• Lap shear strength
• Mass loss

Notes

X: Average, ±s: Standard deviation, V: Coefficient of variation. Homogeneity groups: Same letters (A, B, C, and D) in each column indicate that there is no statistically significant difference among the samples according to the Duncan's multiple range test at p < 0.05. Comparisons were done between the control and test samples. Ten replicates were used in each test. All data in variance and one-way ANOVA tests were conducted at a confidence level of p < 0.05 (95%).