Official Journal of the Japan Wood Research Society
Table 2 Modulus of rupture (MOR) and internal bond strength (IB) of boards subjected to high humidity and humidity cycles
Abbreviations | High humidity | Cyclic humidity | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Exposure time (year) | MOR | IB | Cycle | Exposure time (year) | MOR | IB | |||||
Mean (SD) (MPa) | Retention (%) | Mean (SD) (MPa) | Retention (%) | Mean (SD) (MPa) | Retention (%) | Mean (SD) (MPa) | Retention (%) | ||||
PF board | Initial | 20.3 (2.29) | 0.833 (0.09) | Initial | 20.3 (2.29) | 0.833 (0.09) | |||||
1 | 20.5 (2.62) | 100 | 0.687 (0.05) | 82.8 | 2 | 1 | 17.3 (1.23) | 85.2 | 0.625 (0.06) | 75.4 | |
2 | 17.7 (1.31) | 87.3 | 0.649 (0.10) | 78.2 | 4 | 2 | 17.4 (2.42) | 85.7 | 0.659 (0.06) | 79.4 | |
3 | 14.7 (1.23) | 72.2 | 0.432 (0.09) | 52.0 | 6 | 3 | 20.3 (1.18) | 100 | 0.751 (0.08) | 90.5 | |
5 | 13.7 (0.63) | 67.3 | 0.689 (0.04) | 83.1 | 10 | 5 | 15.1 (1.17) | 74.6 | 0.572 (0.06) | 68.9 | |
MDI board | Initial | 28.8 (2.10) | 2.19 (0.18) | Initial | 28.8 (2.10) | 2.19 (0.18) | |||||
1 | 28.4 (1.08) | 98.5 | 1.96 (0.17) | 89.6 | 2 | 1 | 30.1 (2.59) | 100 | 2.23 (0.18) | 100 | |
2 | 27.6 (2.05) | 96.0 | 1.94 (0.25) | 88.5 | 4 | 2 | 27.0 (1.66) | 93.8 | 1.95 (0.27) | 89.2 | |
3 | 26.5 (1.55) | 92.0 | 1.86 (0.22) | 84.8 | 6 | 3 | 30.6 (1.72) | 100 | 2.04 (0.18) | 93.1 | |
5 | 24.5 (1.51) | 85.0 | 1.85 (0.18) | 84.5 | 10 | 5 | 27.3 (2.70) | 94.9 | 1.89 (0.24) | 86.5 | |
Aspen board | Initial | 39.2 (6.77) | 0.560 (0.13) | Initial | 39.2 (6.77) | 0.560 (0.13) | |||||
1 | 29.3 (3.70) | 74.9 | 0.363 (0.09) | 64.9 | 2 | 1 | 27.3 (3.64) | 69.8 | 0.316 (0.07) | 56.4 | |
2 | 29.6 (5.29) | 75.6 | 0.394 (0.12) | 70.3 | 4 | 2 | 29.1 (5.10) | 74.3 | 0.309 (0.08) | 55.2 | |
3 | 29.8 (2.61) | 76.1 | 0.374 (0.09) | 66.8 | 6 | 3 | 30.8 (3.09) | 78.7 | 0.424 (0.09) | 75.6 | |
5 | 29.0 (6.03) | 74.1 | 0.383 (0.10) | 68.5 | 10 | 5 | 25.0 (7.68) | 63.8 | 0.183 (0.07) | 32.8 | |
Pine board | Initial | 36.8 (7.75) | 0.640 (0.19) | Initial | 36.8 (7.75) | 0.640 (0.19) | |||||
1 | 31.5 (5.47) | 85.7 | 0.525 (0.12) | 82.0 | 2 | 1 | 28.4 (4.41) | 77.2 | 0.509 (0.11) | 79.6 | |
2 | 36.2 (4.90) | 98.3 | 0.596 (0.13) | 93.1 | 4 | 2 | 34.6 (5.22) | 93.9 | 0.477 (0.14) | 74.5 | |
3 | 30.7 (4.08) | 83.4 | 0.434 (0.12) | 67.8 | 6 | 3 | 36.7 (7.05) | 99.6 | 0.552 (0.14) | 86.2 | |
5 | 30.0 (4.14) | 81.4 | 0.524 (0.15) | 81.9 | 10 | 5 | 33.7 (3.75) | 91.5 | 0.463 (0.12) | 72.3 | |
F-MDI board | Initial | 36.1 (2.44) | 1.22 (0.19) | Initial | 36.1 (2.44) | 1.22 (0.19) | |||||
1 | 35.9 (1.09) | 99.4 | 1.04 (0.07) | 85.2 | 2 | 1 | 35.1 (1.85) | 97.1 | 1.22 (0.07) | 99.8 | |
2 | 36.4 (0.97) | 100 | 1.16 (0.25) | 94.8 | 4 | 2 | 33.7 (1.25) | 93.4 | 1.46 (0.18) | 100 | |
3 | 32.4 (2.03) | 89.7 | 1.09 (0.18) | 89.5 | 6 | 3 | 35.6 (2.42) | 98.6 | 1.28 (0.14) | 100 | |
5 | 32.3 (2.02) | 89.6 | 1.17 (0.19) | 96.3 | 10 | 5 | 32.6 (1.43) | 90.3 | 1.11 (0.06) | 91.0 | |
F-MUF board | Initial | 45.4 (2.94) | 0.620 (0.11) | Initial | 45.4 (2.94) | 0.620 (0.11) | |||||
1 | 43.0 (4.03) | 94.6 | 0.480 (0.10) | 77.4 | 2 | 1 | 43.0 (2.28) | 94.6 | 0.718 (0.08) | 100 | |
2 | 43.1 (3.86) | 94.8 | 0.692 (0.11) | 100 | 4 | 2 | 41.6 (2.34) | 91.6 | 0.592 (0.08) | 95.4 | |
3 | 40.6 (3.28) | 89.4 | 0.656 (0.10) | 100 | 6 | 3 | 41.8 (1.08) | 92.0 | 0.775 (0.07) | 100 | |
5 | 35.7 (3.01) | 78.6 | 0.601 (0.08) | 97.0 | 10 | 5 | 39.3 (1.17) | 86.5 | 0.646 (0.08) | 100 | |