Experimental Study on the Load Bearing Behaviour of Textile Reinforced Concrete under Uniaxial Compression – Phase II: Influence of Lateral Compression and Tension

单轴压缩下织物增强混凝土承载性能试验研究Ⅸ阶段：侧向压缩和拉伸的影响

• 批准号: 235549595
• 负责人: Professor Dr.-Ing. Manfred Curbach
• 金额: --
• 依托单位: Institut für Massivbau
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/235549595?language=en
• 关键词: Experimental; Study; Load; Bearing; Behaviour

Investigations of the applicant show that the influence of textile grids on the load-bearing behaviour of textile reinforced concrete (TRC) under compression is not negligible. In addition to the impact of textiles, the tests showed that even the manufacturing process by manual lamination affects the specimen’s maximum strength negatively in regard to casted ones. Furthermore, the orientation of the layers to the loading direction has a significant influence on the concrete strength. The anisotropic material behaviour of unreinforced specimens, which were manufactured layer by layer, is even stronger for TRC specimens. Here, the variation of the orientation of the textile plane leads even to different failure modes. If the textiles are aligned parallel to the loading direction, a brittle failure occurs. On the other hand, a perpendicular alignment of the textiles to the loading direction will cause a quite ductile behaviour. These differences are probably due to two opposing mechanisms. On the one hand, the textiles act as a discontinuity, because they cannot transfer any compressive stresses perpendicular to their longitudinal direction. This causes diversions in the stress field in the specimen. These disturbances induce additional tensile stresses into the concrete, which lead to an accelerated failure. On the other hand, the textiles cause a lateral constraint, and stabilize the specimens during the loading process. These mechanisms dominate material behaviour and failure mode especially if the textiles are aligned perpendicular to the loading direction. The variation of different parameters, like layer spacing, yarn diameter, mesh size or the use of textile layers located offset from each other showed the various impact factors on the material behaviour of TRC under compression. A result of all tests is that the influence of the single parameters on the strength and the anisotropy decreases with a taller layer spacing.What is open is the question of the transferability of the findings of the obtained results to practical components. A first step towards the solution is to be carried out in the second phase of the project by investigating the biaxial material behaviour of TRC under compression-compression and compression-tension loads, because in most of the structural members, there is a multiaxial stress state, e.g. at beams, which are exposed to shear or torsional loads. The planed tests should mainly investigate the impact of the following parameters: kind of textile reinforcement, manufacturing process and different stress ratios. The results of the uni- and biaxial tests are supposed to be a basis for a numerical material model to conduct virtual parameter studies on large-scale concrete members, like beams or columns. The goal of the numerical calculations is to reduce the number of test on such concrete members, which are quite complex and expensive, but necessary for validation of an engineering model in a 3rd funding period.

申请人的调查表明，纺织网格对纺织钢筋混凝土（TRC）在压缩下的承载性能的影响不可忽略。除了纺织物的影响之外，测试表明，即使是手工层压的制造工艺也会产生影响。与浇铸的试件相比，试件的最大强度有负面影响。此外，各层相对于加载方向的方向对混凝土强度有显着影响，逐层制造的无筋试件的各向异性材料行为是均匀的。此处，织物平面方向的变化甚至会导致不同的失效模式。如果织物平行于加载方向排列，则会发生脆性失效。这些差异可能是由于两种相反的机制造成的，一方面，织物表现为不连续性，因为它们不能垂直于其纵向传递任何压应力。这些扰动会导致混凝土中产生额外的拉应力，从而导致加速失效。另一方面，织物会产生横向约束，并在加载过程中稳定样本。材料行为和失效模式，特别是当纺织品垂直于加载方向排列时，不同参数的变化，如层间距、纱线直径、网格尺寸或相互偏移的纺织品层的使用，显示了对材料性能的各种影响因素。 TRC的材料行为所有测试的结果是，单个参数对强度和各向异性的影响随着层间距的增加而减小。首先需要解决的问题是所获得的结果是否可转移到实际部件中。解决方案的步骤将在项目的第二阶段进行，通过研究 TRC 在压缩和压缩拉伸载荷下的双轴材料行为，因为在大多数结构构件中，存在多轴应力状态，例如在承受剪切或扭转载荷的梁，平面试验应主要研究以下参数的影响：织物增强材料的种类、制造工艺和不同的应力比。单轴和双轴试验的结果应该是。数值材料模型的基础，用于对大型混凝土构件（如梁或柱）进行虚拟参数研究。数值计算的目标是减少对此类混凝土构件的测试数量，这些测试相当复杂且昂贵，但却是必要的。用于验证工程模型第三资助期。