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

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.