Mixed Mode Fracture of Concrete

这项研究的目的是继续以前的研究。 华盛顿大学对混合型混凝土断裂的研究 钢筋混凝土构件的斜拉破坏方面。 具体地说，剪切传递机制，这被认为是 抵抗稳定的裂纹扩展，将使用裂纹线楔进行研究- 加载，双悬臂梁试样与短启动裂纹 以及与裂纹长度相关的各种载荷历史。 莫尔干涉法将用于同时测量两个 裂纹张开的正交位移场 稳定扩展斜拉裂纹的位移和滑移 将被确定。 莫尔数据与加载数据一起将 与有限元代码交互使用，以推导出 断裂过程区的裂纹闭合力和剪切力 混合模式加载 混合型稳定裂纹扩展准则 可以从这个混合实验-数值分析中推导出来。 的 结果将与断口分析和轮廓仪相关联 分析断裂表面，以评估相对 各种成分的微观力学贡献（硬化 水泥浆、粗骨料、细骨料等）到混合 混凝土断裂模式

The objective of the proposed research is to continue prior University of Washington studies on mixed-mode concrete fracture aspects of diagonal tension failure in reinforced concrete members. Specifically, the shear transfer mechanism, which is thought to resist stable crack growth, will be studied using crack-line wedge- loaded, double cantilever beam specimens with short starter cracks and various loading histories which are crack-length dependent. Moire interferometry will be used to measure simultaneously two orthogonal displacement fields from which the crack opening displacement and the slip of stably growing diagonal tension cracks will be determined. Moire data together with the loading data will be used interactively with a finite element code to deduce the crack closure and shear forces in the fracture process zone under mixed mode loading. Mixed mode stable crack growth criterion will be deduced from this hybrid experimental-numerical analysis. The results will be correlated with fractography and profilometer analyses of the fractured surfaces in order to assess the relative micromechanic contributions of the various constituents (hardened cement paste, coarse aggregate and fine aggregate, etc.) to mixed mode concrete fracture.