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Creep Properties of Densified Wood in Bending
| Content Provider | MDPI |
|---|---|
| Author | Han, Lei Kutnar, Andreja Couceiro, José Sandberg, Dick |
| Copyright Year | 2022 |
| Description | Thermo-hydro-mechanical (THM)-densified timber is rarely used in construction, although its mechanical properties are in many cases excellent. The main reason for its rare use is set-recovery, which reduces the degree of densification over time so that the mechanical properties deteriorate. Our knowledge of the long-term creep of densified timber is insufficient and a full understanding of its long-term behaviour is still lacking. The purpose of this study was to examine the behaviour under long-term loading of Scots pine sapwood densified in an open system at 170–200 °C. The influence of the THM densification process on the creep properties was studied on (1) unmodified specimens, (2) THM-densified specimens, (3) THM-densified specimens that had been further thermally treated, and (4) low-molecular-weight phenol-formaldehyde resin-impregnated and THM-densified specimens. All specimens were loaded at 20 ± 2 °C and 65 ± 5% relative humidity for 14 days under 3-point bending at 35% of the short-term ultimate load, and the bending deformation was registered. The THM densification doubled the density, causing a significant increase in the modulus of rupture but no change in the modulus of elasticity, and reduced the equilibrium moisture content and creep compliance. Post-thermal modification and resin impregnation improved the dimensional stability and further reduced the creep compliance in bending. The results demonstrate that THM densification combined with resin-impregnation or thermal modification reduces the creep of Scots pine timber under a long-term bending load in a constant climate. |
| Starting Page | 757 |
| e-ISSN | 19994907 |
| DOI | 10.3390/f13050757 |
| Journal | Forests |
| Issue Number | 5 |
| Volume Number | 13 |
| Language | English |
| Publisher | MDPI |
| Publisher Date | 2022-05-14 |
| Access Restriction | Open |
| Subject Keyword | Forests Paper and Wood Thermo-hydro-mechanical Densification Scots Pine Creep Compliance Thermal Modification Resin Impregnation |
| Content Type | Text |
| Resource Type | Article |
