Statistical Analysis of douglas-fir LVL

51 A strong relationship between density of solid wood and of LVLs with bending properties was observed by numerous authors Kilic et al. 2006; Shukla and Kamdem 2007 ; H’ng et al. 2010. In general, LVL density of jabon had higher values than sengon. This fact was caused by the higher density of jabon veneer compared to sengon veneers. The average veneer densities of sengon were 287.0 kgm -3 unboiled sengon and 318.4 kgm -3 boiled sengon. The average veneer densities of unboiled and boiled jabon were 395.3 and 406.9 kgm -3 , respectively. Figure 28 LVL density from pith to bark made of unboiled and boiled sengon a and jabon b veneers

4.6.2 Effect of lathe check on glue bond strength of LVL

The average glue bond strengths of the LVL increased from pith to bark for unboiled and boiled of sengon and jabon Figure 29a-b. The average glue bond strength of unboiled and boiled sengon type I were 35.8, 38.2 kgcm -2 , respectively. Otherwise the average glue bond strengths of unboiled and boiled sengon type II were 39.8 and 43.1 kgcm -2 , respectively Figure 29a. The average glue bond strengths of jabon LVL were 39.8 kgcm -2 unboiled type I, 45.5 kgcm -2 boiled type I, 43.2 kgcm -2 unboiled type II and 50.7 kgcm -2 boiled type II Figure 27b. Figure 29 Glue bond strength of LVL from pith to bark made of unboiled and boiled sengon a and jabon b 300 350 400 450 500 550 600 1 2 3 4 5 6 7 8 L VL d en sity kg m -3 Segmented rings from pith to bark Unboiled sengon type I Boiled sengon type I Unboiled sengon type II Boiled sengon type II a 400 450 500 550 600 1 2 3 4 5 6 7 8 L VL d en sity kg m -3 Segmented rings from pith to bark Unboiled jabon type I Boiled jabon type I Unboiled jabon type II Boiled jabon type II b 20 40 60 80 1 2 3 4 5 6 7 8 Glu e bo nd s tren gth kg cm -2 Segmented rings from pith to bark Unboiled sengon type I Boiled sengon type I Unboiled sengon type II Boiled sengon type II 20 40 60 80 1 2 3 4 5 6 7 8 Glu e bo nd s tr en gth kg cm -2 Segmented rings from pith to bark Unboiled jabon type I Boiled jabon type I Unboiled jabon type II Boiled jabon type II a b