Moisture and Temperature Influence on Biocomposites-to-Timber Bonding

Abstract:

Compatibility and durability are fundamental aspects to take into account when dealing with strengthening and repair of structural components in existing buildings. In particular, timber elements in floors and roofs, like beams and joists, can be improved in their load-bearing capacity by the use of composite (fiber-reinforced) materials. Applied as textiles or laminates, those materials can provide additional tensile strength without weight increase, and are easily applied in situ. Recently, an increasing interest towards the biocomposites (flax, hemp) opened new perspectives: the advantages in comparison with traditional FRPs includes the higher mechanical compatibility and sustainability, especially if glues suitable for wood (e.g., vinyl) are used as matrix, instead of epoxy resins.In the paper, the results of an experimental campaign carried out at the University of Padua, aimed at investigating the influence of humidity and temperature on the adhesion of composite materials (carbon or glass FRP) and biocomposites (flax) reinforcing spruce timber elements are presented. Epoxy resins were used as matrix for all composites; flax was also applied with vinyl glue and considering a protective treatment (alkaline-based). Effectiveness of bond at the interface timber-reinforcement was measured by pull-off tests, and analyzed at micro-structural level by optical microscopy and infrared spectroscopy.

• Periodical: Advanced Materials Research (Volume 778)
• Pages: 561-568
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.778.561
• Online since: September 2013
• Authors: Maria Rosa Valluzzi, Fabiola Nardon, Enrico Garbin, Matteo Panizza
• Keywords: Biocomposite, Compatibility, Durability, Moisture, Temperature, Timber

References

[1] C. Modena, M.R. Valluzzi, F. da Porto, F. Casarin, Structural aspects of the conservation of historic masonry constructions in seismic areas: remedial measures and emergency actions, Int. J. of Architectural Heritage. 5(4-5) (2011) 539-558.

DOI: 10.1080/15583058.2011.569632

[2] M.R. Valluzzi, P. Girardello, D. Francescato, S. Pospíšil, R. Král, D. D'ayala, S. Paganoni, L. Pelà, P. Roca, J. Branco, K. El Harrouni, B. Kucukdogan, M.A. Parisi, Optimization of design for floors, roofs and vaults, in: Proc. of SACH2012 Struct. Analysis of Historical Constr., Wroclaw, Poland, 2012, pp.2879-2887.

[3] N. Gattesco, L. Macorini, High reversibility technique for in-plane stiffening of wooden floors. In: Proc. of SAHC08, Struct. Analysis of Historic Constr., Bath, UK, 2008, p.1035–1042.

DOI: 10.1201/9781439828229.ch118

[4] J. Broughton, A. R. Hutchinson, Effect of timber moisture content on bonded-rods, Construction and Buildings Materials. 15 (2000) 17-25.

DOI: 10.1016/s0950-0618(00)00066-0

[5] J. G M. Raftery, M. A. Harte, P.D. Rodd, Bond quality at the FRP-wood interface using wood-laminating adhesives, International Journal of Adhesion & Adhesives, 29 (2009) 101-110.

DOI: 10.1016/j.ijadhadh.2008.01.006

[6] M.R. Valluzzi, E. Garbin, C. Modena, Flexural strengthening of timber beams by traditional and innovative techniques, Journal of Building Appraisal, 3 (2007) 125-143.

DOI: 10.1057/palgrave.jba.2950071

[7] J. Custodio, J. Broughton, H. Cruz, A review of factors influencing the durability of structural bonded timber joints, Int. Journal of Adhesion & Adhesives, 29 (2009) 173-185.

DOI: 10.1016/j.ijadhadh.2008.03.002

[8] J.J. Maya, T. Sabu, Biofibres and biocomposites, Carbohydrate Polymers, 71 (2008) 343–364.

[9] F. Nardon, M.R. Valluzzi, R. Bertoncello, E. Garbin, Influence of moisture and thermal cycles in bonding of FRP laminates on timber elements, in: Proc. of SHATIS11 Int. Conf. on Structural Health Assessment of Timber Structures, Lisbon, Portugal, 2011, 14 pp. (on CD-ROM).

[10] Giordano, G. (1999), Tecnica delle costruzioni in legno, Milano, Hoepli.

[11] DIN EN 204 (2001), Classification of thermoplastic wood adhesives for non-structural applications.

[12] S. Kalia, B.S. Kaith, I. Kaur, Pretreatments of Natural Fibers and their Application as Reinforcing Material in Polymer Composites – A Review, Polymer Engineering and Science, 49 (2009) 1253-1272.

DOI: 10.1002/pen.21328

[13] A. Stocchi, B. Lauke, A. Vàzquez, C. Bernal, A novel fiber treatment applied to woven jute fabric/vinylester laminates, Composites: Part A, 38 (2007) 1337–1343.

DOI: 10.1016/j.compositesa.2006.10.010

[14] ASTM C 1583-04, Standard Test Method for Tensile Strength of Concrete Surfaces and the Bond Strength or Tensile Strength of Concrete Repair and Overlay Materials by Direct Tension (Pull-off Method).

DOI: 10.1520/c1583_c1583m-20

[15] E. Ciliberto, G. Spoto, Modern Analytical Methods in Art and Archaeology, volume 155 OF Chemical Analysis, Wiley Interscience, U.S.A., (2000).

[16] M. Derrick, D. Stulik, J. Landry, Infrared Spectroscopy in Conservation Science, The Getty Conservation Institute, U. S. A., (1999).