Push-Out Tests on Timber-Concrete Composite Structures Reinforced with Natural Fibres
摘要
Over the last few years, natural fibres such as hemp have emerged as promising alternatives to synthetic fibres for textile reinforcements in structural engineering applications. Their eco-friendly trait, economic feasibility and mechanical properties drew attention to the possibility of using them in less conventional applications such as timber-concrete composites. Timber-concrete composites (TCC) are hybrid structures consisting of timber and concrete elements joined together by a shear-resistant joint. This construction method utilises the strengths of both materials and offers advantages in load-bearing capacity. To assess whether a reliable connection between timber and concrete can be achieved without anchorage devices, push-out tests were conducted on concrete specimens reinforced with multilayer textiles of natural fibres. The textiles were placed in configurations ranging from one to four layers. The results showed that most specimens failed at lower loads than theoretically predicted. A key observation was the formation of a small compression strut angle caused by the absence of anchorage, which reduced the shear capacity of the concrete and governed the failure mechanism. Specimens with one or two layers of reinforcement primarily failed in bending, indicating limited flexural capacity. In contrast, those with three or four layers reached maximum loads comparable to steel-reinforced reference specimens, with failure occurring by concrete notch shearing, timber lamella shearing, or timber compression. These results suggest that increasing the number of textile layers can significantly improve load-bearing capacity. With further refinement of design provisions and consideration of flexural behaviour, textile-reinforced concrete made of natural fibres could contribute meaningfully to more sustainable building solutions.