Influence of Fracture Surface Roughness Characteristics on the Specific Fracture Energy of Concrete as a Function of Specimen and Aggregate Size

断裂表面粗糙度特性对混凝土特定断裂能的影响（作为试样和骨料尺寸的函数）

• 批准号: 9713997
• 负责人: Roberto Ballarini
• 金额: $ 13.42万
• 依托单位: Case Western Reserve University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-02-15 至 2000-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9713997&HistoricalAwards=false
• 关键词: Influence; Fracture; Surface; Roughness; Characteristics

9713997 Perdikaris The influence of the microscale and concrete compressive strength on the fracture energy per unit crack surface area will be evaluated by studying the roughness characteristics of a fracture surface, such as the surface roughness index, fractal dimension and wavelength content. The major objectives of this research are: a) to perform 3-point bending tests under CMOD control on concrete beam specimens of three sizes with three maximum aggregate sizes and three concrete compressive strengths and determine the roughness characteristics of the fracture surfaces, that is the roughness index, fractal dimension, and Fourier amplitude spectra for each fracture surface b) to study the roughness characteristics of the fracture surfaces and to evaluate their dependence on the maximum aggregate size and concrete compressive strength and their influence on the "load vs. load-point-displacement" response and the specific fracture energy. c) to develop a micromechanics-based semi-empirical analysis, wherein the apparent toughness will be calculated based on the given roughness characteristics of the observed crack paths and aggregate size. This research program will be undertaken through a university- state-industry collaboration. The results will improve the methods of specification and evaluation of the performance of normal and high strength concrete resulting in more efficient designs.

9713997 Perdikaris微观尺度和混凝土抗压强度对每单位裂纹表面积断裂能的影响将通过研究断裂表面的粗糙度特性（例如表面粗糙度指数、分形维数和波长含量）来评估。 这项研究的主要目标是： a）、 在CMOD控制下进行三点弯曲测试， 三种尺寸的混凝土梁试件， 骨料尺寸和三种混凝土抗压强度， 确定断裂表面的粗糙度特征， 即粗糙度指数、分形维数和傅立叶 每个断裂面的振幅谱 B） 研究裂缝的粗糙度特征 表面，并评估其对最大值的依赖性 骨料粒径和混凝土抗压强度及其 对“载荷与载荷点位移”响应的影响， 特定的断裂能。 c）、 为了开发基于微观力学的半经验分析， 其中表观韧性将基于 给定所观察到的裂纹路径的粗糙度特性， 骨料粒径 该研究计划将通过大学-国家-行业合作进行。 研究结果将改进普通和高强混凝土性能的规范和评估方法，从而提高设计效率。