Influence of drying in temperatures between 70 °C and 125 °C on selected wood properties of Norway spruce
2001 (English)In: Moisture control in environment-friendly housing and wood drying technology in new century: July 9-13, 2001 Tsukuba, Japan / [ed] K. Hayashi, Forestry and Forest Products Research Institute , 2001, 306-311 p.Conference paper (Refereed)
The present study deals with the influence of drying schedule on the strength and the stiffness of Norway Spruce timber. A previous study gave 11.5 % lower bending strength of timber dried at 115°C compared to timber dried under conventionally (70°C) low temperatures. No influence of high temperature drying on the stiffness was found. These results are in the present paper further evaluated. Special attention is made to the influence of the drying process on the strength and stiffness of structural timber. A comparative study with the mechanical properties of old timber from buildings more than 50 years old is planned.A total number of 634 logs from two regions in Sweden were sawn into planks of dimension 50 mm x 150 mm. The planks were pre sorted in terms of raw stiffness by a stress grading machine. This resulted in eight groups of 156 planks with equal stiffness in the raw condition. Six different drying schedules in maximum dry temperatures ranging from 70 °C to 125 °C were applied to different groups of planks, including a test made to study the effects on the wood during the heating phase to 125 °C.After non destructive evaluation of the dried material by machine stress grading and optical scanning, the mechanical properties of the dried wood was determined. Both bending- and tension strength were evaluated. Failure modes with special concern to failure close to knots are being analysed. Fracture energy is determined for samples from each drying schedule.The results from the present study will give new information on the influence of high temperature drying on strength and stiffness of structural timber. As a wide range of drying schedules are studied valuable information for the optimisation of drying schedules as well as stress grading will be available.
Place, publisher, year, edition, pages
Forestry and Forest Products Research Institute , 2001. 306-311 p.
IdentifiersURN: urn:nbn:se:ltu:diva-32529Local ID: 70d581eb-daf6-4886-bc8a-88f6b988b215OAI: oai:DiVA.org:ltu-32529DiVA: diva2:1005763
International IUFRO Wood Drying Conference : 09/07/2001 - 13/07/2001
För godkännande; 2016; Bibliografisk uppgift: In thesis: Drying and thermal modification of wood - studies on influence of sample size, batch size, and climate on wood response; 20160524 (jacnas)2016-09-302016-09-302016-10-19