Investigation of the behaviour of adhesively bonded joints between timber and self-compacting concrete

Abstract

Composite constructions made of wood and concrete are being researched as revolutionary structural components that offer many benefits. The connection in timber-concrete-composite (TCC) is typically made via mechanical means. This study describes the TCC bonded by adhesives, particularly the mechanical behaviour of the joints between timber (GL24h) and self-compacting concrete (SCC) set by the dry or wet bonding process. For this purpose, double push-out shear tests on TCC joints bonded by epoxy resin of adhesives were performed. The role of several variables was considered for both fabrication processes. These parameters were: variation of moisture content (m.c.) of timber, adhesive type, adhesive thickness, sand addition, concrete surface treatment, and scale of bonding length. The results showed that glueing seems to be a feasible alternative instead of mechanical means for producing dry and wet TCC joints. Under dry conditions of timber elements, the shear strength can be considered highly satisfactory, with a mean value range of 6–8 MPa. The failure mode is primarily affected by concrete and timber failure. However, the findings of this study confirm the hypothesis that increasing the moisture content of timber before the gluing process significantly reduces the shear strength of adhesively bonded TCC joints by approximately 30% in certain instances. These results contribute to understanding the challenges and limitations of the bonding system, providing valuable insights for optimizing the design and manufacturing of timber-concrete composites.

Keywords:

• Timber-concrete composites
• shear strength
• push-out test
• epoxy adhesive bonding

Acknowledgements

The authors would like to thank and acknowledge technicians from the National Institute of Applied Sciences of Toulouse, and GA Smart Building Co., for their assistance during the experimental works. The appreciation would also be extended to SIKA Co. for gracefully supplying resins and discussing the mechanical performance of used resins.

Disclosure statement

The authors have no competing interests to declare that are relevant to the content of this article.

Data availability statement

The raw data required to reproduce these findings are available from the corresponding author upon reasonable request.

Additional information

Funding

The research was financially supported by the GA Smart Building Co.