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

Ercan, Ersin; Aydin, Kadir; Özder, Cansu; Atar, Musa

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

Folia Forestalia Polonica

Volume 64 (2022): Issue 4 (December 2022)

By:

Ersin Ercan, Kadir Aydin, Cansu Özder and Musa Atar

Open Access

|Dec 2022

Figures & Tables

Cutting pattern of heart planks from a log

Hydraulic press used in densification processes

Tensile performance according to wood species, densification ratio, dowel diameter and glue type

Pre-compression dimensions of draft test samples

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

Test parameters

Poplar	800 × 10 × 8	PVAc	Control	6	Eastern spruce	800 × 10 × 8	PVAc	Control	6
			50%	6				50%	6
			75%	6				75%	6
		D-VTKA	Control	6			D-VTKA	Control	6
			50%	6				50%	6
			75%	6				75%	6
	800 × 10 × 10	PVAc	Control	6		800 × 10 × 10	PVAc	Control	6
			50%	6				50%	6
			75%	6				75%	6
		D-VTKA	Control	6			D-VTKA	Control	6
			50%	6				50%	6
			75%	6				75%	6

Tensile performance test results according to wood species

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

Descriptive Statics

Parameters			Tensile performance (kg/cm²)^*
densification	dowel diameter (mm)	glue type	poplar	eastern spruce
control	8	PVAc	177.302	139.665
	8	D-VTKA	176.582	206.168
	10	PVAc	171.640	134.923
	10	D-VTKA	154.833	178.178
50%	8	PVAc	227.615	183.760
	8	D-VTKA	226.072	192.995
	10	PVAc	160.153	187.593
	10	D-VTKA	110.105	115.582
75%	8	PVAc	177.780	189.280
	8	D-VTKA	203.208	222.127
	10	PVAc	159.003	303.547
	10	D-VTKA	120.853	136.205

Technical properties of the hydraulic press

Press temperature	Compression ratio
Pressure capacity	100 ton – 250 Bar
Temperature range	0–250°C
Pressure piston stroke	500 mm
Table size	60 × 60 cm
Motion	auto/manual, 8–11 mm/sec.

Density values and moisture content of dowels

Densification ratio	Density values (g/cm³)		Moisture content (%)
Densification ratio	poplar	eastern spruce	poplar	eastern spruce
Control	0.390	0.401	8.218	8.925
50%	0.508	0.540	4.558	6.485
75%	0.622	0.629	4.381	5.187

Tensile performance (kg/cm2) test results according to quadruple (Duncan Test) interactions

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

Densification process

Densification
Press temperature	Compression ratio	Time
140°C	50%	press heating + 15 minutes
140°C	75%	press heating + 15 minutes

Tensile performance test results according to binary interactions

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

Variance analysis of tensile performance test

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

DOI: https://doi.org/10.2478/ffp-2022-0021 | Journal eISSN: 2199-5907 | Journal ISSN: 0071-6677

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Language: English

Page range: 214 - 225

Submitted on: Jan 27, 2022

Accepted on: Mar 10, 2022

Published on: Dec 10, 2022

Published by: Forest Research Institute

In partnership with: Paradigm Publishing Services

Publication frequency: 4 issues per year

Keywords:

dowel tensile performance,

glue,

Related subjects:

© 2022 Ersin Ercan, Kadir Aydin, Cansu Özder, Musa Atar, published by Forest Research Institute
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

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

Figures & Tables

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Pre-compression dimensions of draft test samples

Test parameters

Tensile performance test results according to wood species

Compression ratios in air dry moisture after densification processes

Descriptive Statics

Technical properties of the hydraulic press

Density values and moisture content of dowels

Tensile performance (kg/cm2) test results according to quadruple (Duncan Test) interactions

Densification process

Tensile performance test results according to binary interactions

Variance analysis of tensile performance test

Paradigm

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