摘要
界面区是水泥混凝土结构中的薄弱区域,为揭示华北地区路面混凝土界面区结构在实际工作环境中的损伤机理,通过室内试验模拟路面混凝土在荷载、冻融和干湿三场耦合下的工作状态,采用数字图像处理技术对不同工作阶段的路面混凝土界面区结构进行图像提取与分析,揭示路面水泥混凝土在三场耦合下界面区结构的动态变化过程,进而研究三场耦合作用下路面水泥混凝土细观损伤机制.结果表明:标准养护3个月后混凝土的界面区宽度在30~40μm之间;随着荷载、冻融和干湿循环三场耦合作用时间的增长,混凝土疲劳寿命明显缩短,达到疲劳破坏时,界面区宽度接近60~70μm;三场耦合作用下界面区的扩展速度明显增加,混凝土的结构密实度逐渐降低,最大裂缝长度先延伸然后减小,而裂缝最大宽度则逐渐增加;最终确定了混凝土疲劳破坏时界面区宽度范围以及界面区结构破坏特征参数临界值.
The interfacial transition zone(ITZ)is a weak area in the cement concrete structure.In order to obtain the deterioration behavior of the ITZ suffering the working environment in North China,coupled loading condition of fatigue load,freeze-thaw cycles and dry-wet was conducted to simulate the working condition of pavement concrete.Digital image processing technology was used to extract and analyze the structure of pavement concrete interface area in different working stages,the dynamic process of the interface structure of the pavement cement concrete under the three fields was revealed,and then microcosmic damage mechanism of pavement cement concrete was studied.Results show that after three months of standard curing,the width of ITZ of concrete is between 30~40μm;with the increase of the coupling time of load,freezing-thawing and dry-wet circulation,the fatigue life of concrete is obviously shortened,and when the fatigue damage is reached,the width of ITZ is close to 60~70μm;the expansion rate of ITZ increases obviously,the structural density of the concrete decreases gradually,the maximum crack length extends first and then decreases,and the maximum width of the crack increases gradually;finally,the width of ITZ and the critical value of the structural parameters of ITZ are determined.
作者
郭寅川
林森林
申爱琴
李鹏
周胜波
GUO Yinchuan;LIN Senlin;SHEN Aiqin;LI Peng;ZHOU Shengbo(Key Laboratory of Highway Engineering in Special Region of Ministry of Education,Chang an University,Xi an 710064,Shaanxi, China;Louisiana Transportation Research Center,Louisiana State University,Baton Rouge 70803,Louisiana,USA)
出处
《华南理工大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2018年第6期23-30,共8页
Journal of South China University of Technology(Natural Science Edition)
基金
国家自然科学基金青年基金资助项目(51608047)
国家自然科学基金资助项目(51278059)~~
关键词
路面混凝土
荷载
冻融破坏
三场耦合
界面区
疲劳破坏
损伤机理
pavement concrete
load
freeze-thaw damage
three-fields coupling
interfacial transition zone
fatigue damage
damage mechanism
