基于开裂区平均化方法的混凝土开裂特性

为研究混凝土试件的开裂特性,基于细观力学理论对传统平均化方法进行了改进,提出了开裂区平均化方法。利用不同的平均化方法对级配与粒径分布相同的不同尺寸试件进行计算分析,研究混凝土试件的开裂特性和开裂尺寸依赖性的产生机理。结果表明,开裂区平均化方法能够得到具有尺寸一致性的、表征试件开裂破坏全过程的开裂特性曲线,可确定重要开裂计算参数;开裂尺寸依赖性的出现是由于在试件尺寸变化时,试件中占较小空间的局部开裂区大小及其力学特性基本不受尺寸变化影响,而占较大空间的线弹性区大小及其力学性能却受尺寸变化影响较大,导致整体宏观响应受尺寸变化较大,并由此产生尺寸依赖性。

Concrete cracking characteristic analysis using cracking zone average method

In order to investigate concrete cracking characteristics, the traditional average method was modified based on meso-mechanics theory and used in cracking zones. Using different average methods, concrete specimens with different sizes but the same grading and size distributions were analyzed, and cracking characteristics and mechanisms of cracking size dependency were studied. The results show that cracking stress-strain curves obtained with the cracking zone average method are size independent, and they can represent the entire cracking process and determine important cracking parameters. It is also shown that when the specimen size varies, the area and mechanical characteristics of local nonlinear cracking zones are barely affected by the specimens size change, while the area and mechanical characteristics of linear elastic zones are highly affected by the specimens size change, making the global average mechanical characteristics change a lot, thus the cracking size dependency occurs.