The effect of the densification process on dowel tensile performance with different types of glues

Figures & Tables

Compression ratio	Dimensions (mm)
Compression ratio	length (longitudinal direction)	width (tangent direction)	thickness (radial direction)
50%	800	10	20
75%	800	10	40

Wood species^*	Tensile performance (kg/cm²)X – HG
Eastern spruce	182.50^a
Poplar	173.66^b
Densification ratio^**
75%	191.4^a
50%	175.5^b
Control	167.4^c
Dovel diameter^***
8 mm diameter dowel	195.11^a
10 mm diameter dowel	161.05^b
Types Glue^****
PVAc glue	185.92^a
D-VTKA glue	170.24^b

Compression ratios in air dry moisture after densification processes

Wood	Densification conditions	Thickness before compression	Thickness after compression	Press thickness	Compression ratio	Std.
Poplar	140°C 50%	20 mm	10.14 mm	10 mm	47.80%	0.16
Poplar	140°C 75%	40 mm	10.57 mm	10 mm	73.57%	0.58
Eastern spruce	140°C 50%	20 mm	10.22 mm	10 mm	48.90%	0.31
Eastern spruce	140°C 75%	40 mm	10.86 mm	10 mm	72.85%	0.51

Wood species + Densification ratio + + Diameter of dowel + Glue type	X-HG (kg/cm²)
P + d^50% + 8^mm + PVAc	227.6^a
P + d^50% + 8^mm + Dv	226.1^a
Es + d^75% + 8^mm + Dv	222.1^a
Es + C+8^mm + Dv	206.2^b
P + d^75% + 8^mm + Dv	203.2^bc
P + d^75% + 8^mm + PVAc	196.6^bcd
Es + d^50% + 8^mm + Dv	193.0^cde
Es + d^75% + 8^mm + PVAc	189.3^cde
Es + d^50% + 10^mm + PVAc	187.6^cde
Es + d^50% + 8^mm + PVAc	183.8^cdef
Es + d^75% + 10^mm + PVAc	177.8^def
Es + C+10^mm + Dv	178.2^defg
P + C + 8^mm + PVAc	177.3^defg
P + C + 8^mm + Dv	176.6^efg
Es + C + 10^mm + PVAc	171.6^efg
P + d^50% + 10^mm + PVAc	160.2^fgh
P + d^75% + 10^mm + PVAc	159.0^fghi
P + C + 10^mm + Dv	154.8^ghi
Es + C + 8^mm + PVAc	139.7^hij
Es + d^75% + 10^mm + Dv	136.2^hij
Es + C + 10^mm + PVAc	134.9^ij
P + d^75% + 10^mm + Dv	120.9^jk
Es + d^50% + 10^mm + Dv	115.6^jk
P + d^50% + 10^mm + Dv	110.1^k

Wood + Densification	X-HG	Densification + Diameter	X-HG	Densification + Glue	X-HG
Es + d^75%	212.8^a	d^50% + 8^mm	207.6^a	d^75% + PVAc	212.1^a
P + d^50%	181.0^b	d^75% + 8^mm	202.8^a	d^50% + PVAc	189.8^b
P	170.1^bc	d^75% + 10^mm	179.9^b	C + Dv	178.9^bc
Es + d^50%	170^bc	C + 8^mm	174.9^b	d^75% + Dv	170.6^cd
P + d^75%	169.9^bc	C + 10^mm	159.9^c	d^50% + Dv	161.2^de
Es	164.7^c	d^50% + 10^mm	143.4^d	C + PVAc	155.9^e
LSD = ±11.09		LSD = ±11.12		LSD = ±19.21

Source	Degree of freedom	Sum of square	Mean of square	F	α < 0.05
Wood species (A)	1	2,811.562	2,811.562	7.3974	0.0075^*
Densification (B)	2	14,244.143	7,122.071	18.7386	0.0000^*
AB	2	21,040.921	10,520.461	27.6799	0.0000^*
Diameter (C)	1	41,772.206	41,772.206	109.9050	0.0000^*
AC	1	15,980.963	15,980.963	42.0468	0.0000^*
BC	2	16,775.502	8,387.751	22.0686	0.0000^*
ABC	2	9,586.050	4,793.025	12.6107	0.0000^*
Glue (D)	1	8,853.084	8,853.084	23.2930	0.0000^*
AD	1	43.263	43.263	0.1138	0.0000^*
BD	2	28,015.219	14,007.609	36.8548	0.0000^*
ABD	2	20,149.924	10,074.962	26.5078	0.0000^*
CD	1	42,854.177	42,854.177	112.7517	0.0000^*
ACD	1	9,539.593	9,539.593	25.0992	0.0000^*
BCD	2	15,928.969	7,964.484	20.9550	0.0000^*
ABCD	2	9,423.694	4,711.847	12.3971	0.0000^*
Error	120	45,609.062	380.076
Total	143	302,628.332