The effect of hygro-thermo-mechanical modification on the applied properties of glulam made from poplar

Document Type : Research Paper

Authors

1 Research Institute of Forests and Rangelands, Agricultural Research Education and Extension Organization (AREEO), Tehran, Iran.

2 Department of Wood and Paper Sciences, Faculty of Natural Resources, Tarbiat Modares University, Noor, Iran

Abstract

The objective of this study was to investigate the physical and mechanical properties of glulam made from compressed poplar wood (Populus deltoides) by technique of Combined Hygro-Thermo-Mechanical Treatment (CHTMT) which is combination of two techniques of hygrothermal treatment and densification of wood. The poplar wood blocks were initially treated hygrothermally at temperatures of 130, 150, and 170°C for holding times of 20 and 40 minutes. Afterwards, the densification process was carried out under a hot press (at 160°C for 20 minutes) at two levels of compression set, i.e. 40 and 60 percent based on the blocks thickness (radial direction). For production of glulam, the blocks were jointed together by finger joint and polyurethane resin. The produced glulam were physically and mechanically tested for its water absorption, radial and tangential swelling, delamination, bending strength, modulus of elasticity and shear strength. Results revealed that physical and mechanical properties of glulam were enhanced due to the CHTMT treatment. According to the results, water absorption and radial swelling of glulam were increased due to the CHTMT, significantly. Moreover, this treatment reduced the delamination of samples after soaking- drying cycles. It was also found that the CHTMT could significantly enhance mechanical properties of glulam such as bending strength and bending modulus of the elasticity; but decreases shear strength of glue line. Generally, results showed positive effects of CHTMT in glulam production.

Keywords

References

[1] Andre, A., 2006. Fibres for Strengthening of Timber Structures, Research Report, Forest and Wood Product Research and Development Corporation, Australia, 3: 1–91.
[2] Yang, T.H., Wang, S.Y., Tsai, M.J., and Lin, C.Y., 2009. The Charring Depth and Charring rate of Glued Laminated Timber After a Standard Fire Exposure Test. Building and Environment, 44: 231–236.
[3] Smith, I., Foliente, G., Nguyen, M., and Syme, M., 2005. Capacities of Dowel-Type Fastener Joints in Australian Pine. Journal of Materials in Civil Engineering. ASCE, 17(6): 664–75.
[4] Liu, S., 2008. A kinetic Model on Autocatalytic Reactions in Woody Biomass Hydrolysis. Journal of Biobased Materials and Bioenergy., 2: 135–147.
[5] Garrote, G., Domínguez, H., and Parajó, J.C., 1999. Hydrothermal Processing of Lignocellulosic Materials, Holz als Roh- und Werkstoff, 57: 191–202.
[6] Lam, P.S., 2011. Steam Explosion of Biomass to Produce Durable Pellet, Ph.D. Dissertation, The University of British Columbia, Vancouver, Canada.
[7] Assor, C., Placet, V., Chabbert, B., Habrant, A., Lapierre, C., Pollet, B., and Perre, P., 2009. Concomitant Changes in Viscoelasticity Properties and Amorphous Polymers During the Hydrothermal Treatment of Hardwood and Softwood. Journal of Agricultural and Food Chemistry, 57: 6830–6837.
[8] Biswas, A.K., Yang, W., and Blasiak, W., 2011. Steam Pretreatment of Salix to Upgrade Biomass Fuel for Wood Pellet Production. Fuel Processing Technology., 92: 1711– 1717.
[9] Mitchell, P.H., 1988. Irreversible Property Changes of Small Loblolly Pine Specimens Heated in Air, Nitrogen, or Oxygen. Wood and Fiber Science, 20(3): 320–55.
[10] Stamm, A.J., 1964. Wood and Cellulose Science, New York: Ronald Press, p. 549.
[11] Gong, M., Lamason, C., and Li, L., 2010. Interactive Effect of Surface Densification and Post-Heat- Treatment on Aspen Wood, Journal of Materials Processing Technology., 210: 293–296.
[12] Mohebby, B., Sharifnia-Dizboni, H., and Kazemi-Najafi, S., 2009. Combined Hydro-Thermo-Mechanical Modification (CHTM) as an Innovation in Mechanical Wood Modification, In: Proceeding of 4th European Conference on Wood Modification (ECWM4), Stockholm, Sweden, 353-360.
[13] Navi, P., and Heger, F., 2004. Combined Densification and Thermo-Hydro-Mechanical Processing of Wood, MRS Bull, 29: 332–336.
[14] Tjeerdsma, B.F., and Militz H., 2005. Chemical Changes in Hydrothermal Treated Wood. FTIR Analysis of Combined Hydro Thermal and Dry Heat-Treated Wood. Holz als Roh- und Werkstoff, 63 (2): 102-111.
[15] Khademi, L., and Mohebby B., 2011. Bioresistance of Poplar Wood Compressed by Combined Hydro-Thermo-Mechanical Wood Modification (CHTM): Soft-Rot and Brown-Rot. International Biodeterioration & Biodegradation , 65: 866-870.
[16] Ohnesorge, D., Richter, K., and Becker, G., 2010. Influence of Wood Properties and Bonding Parameters on Bond Durability of European Beech Glulams, Annals of Forest Science, 67 (6): 601.
[17] Standard Methods of Testing Small Clear Specimens of Timber. American Society for Testing of Materials, ASTM D 143-09, 2014.
[18] Standard Test Methods for Strength Properties of Adhesives Bond in Shear by Compression Loading. American Society for Testing of Materials, ASTM D 905-03, 2003.
[19] Timber Structures- Glued Laminated Timber -Test Methods for Determination of Physical and Mechanical Properties, 2: 15. ISO 8375. 2009.
[20] Blomberg, J., 2005. Elastic Strain at Semi-Isostatic Compression of Scots Pine (Pinus sylvestris). Journal of Wood Science., 51: 401–404.
Iranian Journal of Wood and Paper Industries
Volume 11, Issue 2
September 2020
Pages 241-253

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