Measurement of Fracture Toughness of Conrete Using the Short-Rod Procedure

使用短棒法测量混凝土的断裂韧性

• 批准号: 9414243
• 负责人: Anthony Ingraffea
• 金额: --
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-09-15 至 1999-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9414243&HistoricalAwards=false
• 关键词: Measurement; Fracture; Toughness; Conrete; Using

9414243 Ingraffea The objective of this research is to evaluate the short-rod (SR) specimen configuration for use in the standardized measurement of fracture toughness of concrete. Key issues addressed are: 1)Applicability of Linear Elastic Fracture Mechanics (LEFM) testing procedures to ASTM C39 standard cylinder size for low, medium,and high strength concrete; 2)Applicability of cohesive fracture mechanics-based testing procedures for low, medium, and high strength concrete; and 3)The applicability of simplified size-effect adjustment procedures to estimate valid fracture toughness (Klc) The project consists of two principal tasks, testing and simulation. Two levels of SR testing will be performed on three sizes of specimens, and three strengths of concrete. Level 1 will assume LEFM behavior. Level II will account for large scale inelasticity, and could also measure Klc from sub-size specimens. The SR results will be compared to those obtained from testing using the European standard. Computer simulation will be used to: test the validity of the inelasticity correction factor used in Level II testing; assess the consistency and accuracy of this approach for all sizes and strengths tested; and recalibrate the current standard SR geometries for optimal testing of concrete. The results of this project could lead to a reliable, simple, and inexpensive standard test procedure for a concrete property whose measurement is of increasing importance. ***

9414243 Ingraffea本研究的目的是评估短杆（SR）试样配置用于混凝土断裂韧性的标准化测量。 处理的关键问题是： 1)低、中、高强度混凝土的线弹性断裂力学试验程序对ASTM C39标准圆柱尺寸的适用性 2)基于内聚断裂力学的试验程序对低、中、高强度混凝土的适用性; 3)简化的尺寸效应调整程序对估算有效断裂韧度（Klc）的适用性 该项目包括两个主要任务，测试和模拟。 将对三种尺寸的样本和三种强度的混凝土进行两级SR测试。 级别1将采用LEFM行为。 II级将解释大规模的非弹性，也可以测量亚尺寸试样的Klc。 将SR结果与使用欧洲标准进行测试获得的结果进行比较。 计算机模拟将用于： 检验所用非弹性修正系数的有效性 在二级测试中; 评估该方法对于所有测试尺寸和强度的一致性和准确性;以及 重新校准当前的标准SR几何形状，以实现混凝土的最佳测试。 该项目的结果可能会导致一个可靠的，简单的，廉价的标准测试程序的混凝土性能的测量是越来越重要。 ***