Description
The popularity of timber-concrete composite (TCC) systems is attributed to their ability to exploit the best qualities of each of the materials involved. Practically, concrete is used in the compression zone of this composite section, while the timber is situated in the tension region, achieving the best performance of these materials in terms of strength and stiffness. Until recently, timber and concrete are typically connected through mechanical means such as screws, bolts, or indenting the wood with concrete. In the last decade, the technique of structural adhesive bonding has become increasingly popular. By using this technique, as opposed to conventional assemblies (local connectors), the two materials can be connected almost perfectly. In contrast, some precautions are necessary to properly glue timber and concrete, like ensuring that the resin and materials (timber and concrete) are compatible, ensuring that the surface of the materials are prepared properly for bonding and the environment in which they will be applied. Several research works have investigated the bonding of timber (mostly glulam or LVL) to standard concrete from ordinary Portland cement (OPC) or ultra-high performance concrete (UHPC). In comparison with standard concrete, UHPC has higher compressive strength, allowing thin concrete slabs (from UHPC) to be used when bonding to timber. In addition to the contributions of the individual components, the overall performance of the TCC depends on how the timber, adhesive, adhesive joint and concrete interact. This indicates that depending on the type of concrete material and adhesive, the adherence of concrete to wood and its interaction, as well as the contribution to the TCC may differ. Geopolymer is produced by alkaline activation of any aluminosilicate source material. On contact with the alkaline activator solution, the aluminosilicate undergoes dissolution, hydrolysis, and polycondensation, forming an amorphous to semicrystalline solid geopolymer network. How to improve geopolymer concrete and timber interfacial bond strength becomes a critical issue to improve the short-term mechanical performance and long-term durability. In this master thesis, geopolymer concrete will be used as a green concrete in the manufacture of TCC with key focus on the influence of the type of timber product and surface preparation methods for concrete/timber on the wet and dry bonding.
The tasks include:
Contact: Ali Nemati Giv, M. SC., a.nemati-giv(at)tu-bs.de