Final results of the beams made of glued laminated timber (glulam) in the EU CELLUWOOD Project. These results were presented by AIDIMA at the CELLUWOOD Final Workshop on 4th September 2014. During the workshop comprehensive outcomes of the CELLUWOOD project were presented and the future exploitation of the project results was discussed. The project outcomes were presented to the industry stakeholders and the research community. Some valuable feedback on project developed products and technology were obtained by the external workshop participants. The useful contacts were established with potential resin manufacture with an interest for further commercial exploitation of the CELLUWOOD technology, in particular lignin-based and nanocellulose-based gluing systems. CELLUWOOD ( “Laminated Strong Eco-Material for Building Construction Made of Cellulose-Strengthened Wood - Final Outcomes”) was a four years EU project, funded under the Eco Innovation research initiative. The project aims to develop a new range of structural elements made of wood by introducing innovative production elements and includes the use of cellulose instead of petroleum-based glue in the lamination of the timber products. The main results will be the strong eco-beams and eco-columns and their most sustainable manufacturing technologies, in addition to significant environmental and cost benefits of the innovation. These are achieved by the introduction of the (new) technologies from other sectors (e.g. cellulose velvet, biocomposite reinforcement and bio-resin) for innovative uses in the defect removal and repairing, facilitating innovation in the use of nanocellulose and bio-resin technologies in timber reengineering, and the development, testing and demonstration of the new products. The CELLUWOOD products include strong glulam Eco-beams and columns manufactured by using bio-based lignin resins and nanocellulose enhanced glue systems. Both innovative building products provide significant environmental benefits. Coordinator and responsible of the project at AIDIMA: Miguel Ángel Abián In the case of AIDIMA, this project is co-funded by IVACE (Instituto Valenciano de Competitividad Empresarial) and by the European Regional Development Fund (ERDF).

1. CELLUWOOD Project Final Workshop
4th September 2014, Lleida (Spain)
Eco-beams results
AIDIMA
Miguel Ángel Abián

2. 2
WP 8: ASSESSMENT OF CELLUWOOD MATERIAL
The overall objective of this WP is to test and characterize the CELLUWOOD materials developed in the previous WPs. This presentation is focused on the results from beams.

3. 3
Previously, in WP7 some lignin, PUR and MUF beams where manufactured at TECNIFUSTA for interim testing. Those interim tests led to changes in the formulation of the lignin resin by CHIMAR in order to achieve a satisfactory and effective final resin.
In 2014, 20 complete beams (nominal dimensions: 120 x 120 x 2200 mm) were manufactured at TECNIFUSTA in collaboration with CHIMAR and AIDIMA:
•10 beams with their lamellae glued by the final lignin resin developed in the project (CELLUWOOD beams).
•10 beams with their lamellae glued by commercial PUR.
All lamellae were made of timber classified as C24.
10 commercial beams (nominal dimensions: 120 x 120 x 2200 mm) made with MUF resin were used in order to compare strength and behaviour with the other 20 beams. The commercial beams are classified as GL24h.
All beams were made of Picea abies wood.
1. MANUFACTURING OF THE BEAMS TO BE TESTED

4. 4
Measurement of the moisture content of timber
Preparation of the lignin resin for its application

5. 5

6. 6

7. 7

8. 8

9. 9

10. 10

11. 11

12. 12
PUR beams

13. 13

14. 14

15. 15
Shear test of glue lines
EN 392 (Glued laminated timber. Shear test of glue lines).
2. PERFORMANCE OF THE GLUE LINES IN CELLUWOOD BEAMS (LIGNIN RESIN)

16. 16
According to EN 386, the shear strength of each glue line shall be at least 6,0 N/mm2. RIGHT
0
1
2
3
4
5
6
7
8
9
10
1
2
3
4
5
6
7
8
9
10
Shear strength (N/mm2)
Shear strength (fS) of the glue line 1
0
1
2
3
4
5
6
7
8
9
10
1
2
3
4
5
6
7
8
9
10
Shear strength (N/mm2)
Shear strength (fS) of the glue line 2

17. 17
According to EN 386 RIGHT
0
10
20
30
40
50
60
70
80
90
1
2
3
4
5
6
7
8
9
10
PWF (%)
Percentage wood failure (PWF) of the glue line 1
0
10
20
30
40
50
60
70
80
90
100
1
2
3
4
5
6
7
8
9
10
PWF (%)
Percentage wood failure (PWF) of the glue line 2

18. All test pieces fulfilled the requirements of EN 386 (Glued laminated timber. Performance requirements and minimum production requirements) regarding shear strength and wood failure percentage (EN 392). These results point out very clearly that gluing Picea abies lamellae with the lignin resin is very effective.
Average value
SD
fS (N/mm2)
7.37
0.75
PWF (%)
66.0
16.4
18

19. Delamination of glue lines
EN 391 (Glued laminated timber. Delamination of glue lines)
EN 391 is a glulam production standard, which determines if the product is “up to standard”. This test method measures the delamination of flue lines after a treatment consisting of soaking in water followed by fast drying at a high temperature; that is, in effect, an accelerated ageing test method.
Stresses in the wood perpendicular to the glue line put a strain on the joint, which either fails in the flue line (causing a delamination), or creates cracks in the wood. If the delamination value after treatment is low (0% after one cycle, <5% after 2 cycles and <10% after 3 cycles using Method A, which is the treatment method for glulam in service class 3 according to EN 386), the bonding is seen as being successful, and the product can go to the market.
19

20. After each of the three cycles specified in Method A of EN 391, the total delamination percentage and the maximum delamination percentage were 0% for all 10 samples. Therefore, the samples fulfilled the requirements of EN 386 for glue integrity in structures of service class 3.
Considering this and the results from EN 392, all samples fulfilled the requirements of EN 386 regarding glue line integrity and strength for structures of service class 3.
Pressure vessel used by AIDIMA for the first two cycles of Method A (EN 391)
20

21. Two test samples after extracting them from the pressure vessel, following Method A (EN 391).
Test sample after the final drying process specified in Method A (EN 391). There is no delamination in the glue lines.
21

22. All 10 beams were conditioned were in normal environment conditions (relative humidity 65 + 5 %; temperature 20 + 2º C) for 7 days. The points used for measuring moisture content are shown in the following figure.
3. MOISTURE RESISTANCE OF CELLUWOOD BEAMS (LIGNIN RESIN)
22

23. The maximum difference in moisture content between lamellas is <2%, so the dimensional stability of CELLUWOOD beams is excellent.
23

24. 24
Volumetric shrinkage
The standards used for determining the volumetric shrinkage of CELLUWOOD beams were a combination of UNE 56533 (Physical-mechanical characteristics of wood. Determination of linear and volumetric shrinkage) and ISO 4858 (Wood - Determination of volumetric shrinkage) standards.
The International Standard specifies two methods for the determination of the volumetric shrinkage of wood. The method chosen in the project was the mercury volumenometer method, used for test pieces of any shape.

25. 25

26. Sample
βν (%)
ν (%)
SL (parallel to glue line) (%)
SL (parallel to glue line) (%)
SL (longitudinal) (%)
1
10.82
0.25
4.18
5.02
1.16
2
10.33
0.27
4.01
4.46
1.23
3
10.76
0.26
3.96
5.14
1.07
4
10.32
0.30
4.01
4.67
1.03
5
10.45
0.25
4.11
4.81
1.18
6
10.34
0.29
4.00
5.08
1.14
7
9.98
0.24
4.14
4.74
1.01
8
10.43
0.28
3.95
5.06
1.11
9
10.64
0.31
4.14
4.91
1.20
10
10.91
0.25
4.19
4.87
1.12
Average
10.50
0.27
4.07
4.88
1.13
Standard deviation
0.28
0.02
0.09
0.21
0.07
Total volumetric shrinkage: βν
Volumetric shrinkage coefficient: ν
Total linear shrinkage: SL
The total volumetric shrinkage (10.5%) and the volumetric shrinkage coefficient (0.27%) are significantly lower than those corresponding to Norway spruce timber used for the beams (12.6% and 0.45%, respectively). With respect to shrinkage, CELLUWOOD beams are appropriate for outdoor use. They have a good dimensional behaviour regarding shrinkage, compared with standard timber.
26

27. Volumetric swelling
The standard used for determining the volumetric swelling of the CELLUWOOD beams was ISO 4860 (Wood - Determination of volumetric swelling). That Internation Standard specifies two methods for the determination of the volumetric swelling of wood. The method chosen in the project was the mercury volumenometer method, used for test pieces of any shape.
27

28. Total volumetric swelling: ανmax
Volumetric swelling: ανn
Sample
ανmax (%)
ανn (%)
1
10.13
2.87
2
9.91
3.10
3
10.31
2.93
4
10.40
3.21
5
10.28
2.97
6
10.02
3.01
7
9.96
2.85
8
10.38
2.93
9
10.09
3.11
10
10.21
2.90
Average
10.17
2.99
Standard deviation
0.17
0.12
The total volumetric volumetric swelling (10.17%) is significantly lower than those corresponding to Norway spruce timber used for the beams (13.2%). With respect to swelling, CELLUWOOD beams are appropriate for outdoor use. They have a good dimensional behaviour regarding swelling, compared with standard timber.
28

29. 29
3. NON-DESTRUCTIVE TESTS (ULTRASOUNDS)
PUR BEAMS

30. 30
Results for PUR beams:
•Good quality timber in all lamellae: C24-C40
•MOE of lamellae between 10900 and 15700 N/mm2
•All glue lines without cracks, holes or discontinuities

31. 31
COMMERCIAL MUF BEAMS
GL24h

32. 32
Results for commercial MUF beams:
•Good quality timber in all lamellae: C24-C40
•MOE of lamellae between 11551 and 14897 N/mm2
•All glue lines without cracks, holes or discontinuities

33. 33
LIGNIN BEAMS

34. 34
Results for lignin beams:
•Good quality timber in all lamellae: C20-C40
•MOE of lamellae between 10425 and 16534 N/mm2
•All glue lines without cracks, holes or discontinuities

35. 4. MECHANICAL PROPERTIES OF SMALL SAMPLES FROM CELLUWOOD BEAMS
STANDARD
RESULT
Density (kg/m3)
UNE 56531
498
Moisture content (%)
EN 12183-1
10.4
Bending strength (N/mm2)
UNE 56537
80.1
Modulus of Elasticity
UNE 56537
10160
Total volumetric shrinkage (%)
UNE 56533
12.6
Shrinkage coefficient (%)
UNE 56533
0.45
Linear shrinkage. Radial direction (%)
UNE 56533
4.14
Linear shrinkage. Tangential direction (%)
UNE 56533
7.78
Linear shrinkage. Longitudinal direction (%)
UNE 56533
0.26
Higroscopicity (kg/cm3)
UNE 56532
0.0025
Axial compression C12 (kg/cm2)
UNE 56535
476
Compression strength perpendicular to grain. Radial face (N/mm2)
UNE 56542
97.5
Compression strength perpendicular to grain. Tangential face (N/mm2)
UNE 56542
95.6
Shear strength (N/mm2)
UNE 56543
73.6
Tension strength perpendicular to grain. Radial direction (N/mm2)
UNE 56538
11.6
The general properties of the Norway spruce (Picea abies) timber used in CELLUWOOD beams were determined at AIDIMA Laboratories.
Each value shown in the table is the average value of 30 samples (3 samples from each beam).
35

36. According to EN 408:2010, mechanical properties were determined in small samples of CELLUWOOD beams made of Norway spruce (Picea abies) lamellae glued with the final lignin resin developed in the project. When possible, the dimensions of the samples maintained the real geometry of the lamellae of which beams are made.
Bending strength (MOR) and global modulus of elasticity (MOE)
Sample
Bending strength (N/mm2)
Global modulus of Elasticity (N/mm2)
1
71.28
12580
2
73.12
11623
3
81.03
12961
4
76.25
12098
5
68.67
11483
6
78.24
12856
7
74.91
12755
8
66.94
12136
9
72.27
13546
10
78.23
13865
Average
74.09
12590
Standard deviation
4.48
773
Characteristic value of MOR for glulam classified as GL24h: 24 N/mm2
Characteristic value of MOE for glulam classified as GL24h: 11600 N/mm2
36

37. Compression strength parallel to grain
Sample
Compression strength parallel to grain (N/mm2)
1
42.50
2
44.12
3
40.21
4
44.62
5
41.37
6
44.06
7
42.48
8
43.81
9
41.95
10
44.23
Average
42.94
Standard deviation
1.46
Characteristic value of this property for glulam classified as GL24h: 24 N/mm2
Characteristic value of this property for glulam classified as GL36h: 31 N/mm2
37

38. Compression strength perpendicular to grain
Sample
Compression strength perpendicular to grain (N/mm2)
1
3.93
2
4.19
3
4.23
4
3.91
5
4.11
6
3.85
7
4.18
8
3.96
9
4.12
10
3.88
Average
4.03
Standard deviation
0.14
Characteristic value of this property for glulam classified as GL24h: 2.7 N/mm2
Characteristic value of this property for glulam classified as GL36h: 3.6 N/mm2
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39. 39

40. Shear strength
Sample
Shear strength (N/mm2)
1
6.60
2
5.51
3
5.93
4
6.07
5
6.23
6
5.79
7
6.01
8
5.86
9
6.33
10
5.98
Average
6.03
Standard deviation
0.30
Characteristic value of this property for glulam classified as GL24h: 2.7 N/mm2
Characteristic value of this property for glulam classified as GL36h: 4.3 N/mm2
40

41. 41

42. Tension strength parallel to grain
Sample
Tension strength parallel to grain (N/mm2)
1
21.31
2
20.67
3
19.48
4
20.71
5
21.46
6
19.92
7
20.52
8
19.78
9
20.07
10
21.56
Average
20.55
Standard deviation
0.73
Characteristic value of this property for glulam classified as GL24h: 16.5 N/mm2
Characteristic value of this property for glulam classified as GL28h: 19.5 N/mm2
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43. Tension strength perpendicular to grain
Sample
Tension strength perpendicular to grain (N/mm2)
1
1.92
2
1.77
3
1.56
4
1.89
5
1.48
6
1.79
7
1.84
8
1.43
9
1.91
10
1.42
Average
1.70
Standard deviation
0.21
Characteristic value of this property for glulam classified as GL24h: 0.4 N/mm2
Characteristic value of this property for glulam classified as GL36h: 0.6 N/mm2
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45. 45
EN 408:2011+A1:2012 Timber structures – Structural timber and glued laminated timber – Determination of some physical and mechanical properties specifies test methods for determining most of the strength and stiffness properties of structural and glued laminated timber.
Section 19. Determination of bending strength
Section 10. Determination of global modulus of elasticity in bending
5. MECHANICAL PROPERTIES OF CELLUWOOD BEAMS DETERMINED FROM FULL-SIZE SPECIMENS

46. 46

47. 47
Breaking of a commercial MUF beam

48. 48
Breaking of a commercial MUF beam

49. 49
Breaking of a PUR beam

50. 50
Breaking of a PUR beam

51. 51
Breaking of a lignin beam (separation of the lamellas)

52. 52
Breaking of a lignin beam (separation of the lamellas)

53. 53
Breaking of a lignin beam (crack)

54. 54
Breaking of a lignin beam (crack)

55. 55
10000
12000
14000
16000
18000
20000
22000
24000
MOE (MPa)
MUF
PUR
LIGNIN

56. 56
The average MOE for lignin beams is 45% greater than the average MOE for MUF beams
12425
15135
18027
10000
11000
12000
13000
14000
15000
16000
17000
18000
19000
MUF
PUR
LIGNIN
Average MOE (MPa)

57. 57
40
45
50
55
60
65
70
75
MOR (MPa)
MUF
PUR
LIGNIN

58. 58
The average MOR for lignin beams is 23% greater than the average MOR for MUF beams
49,6
51,2
61,0
40
45
50
55
60
65
MUF
PUR
LIGNIN
MOR (MPa)

59. Thank you very much for your attention
Project coordinator at AIDIMA: Miguel Ángel Abián