摘要
研究应力腐蚀对岩土预应力锚索长期耐久性的影响可以有效减少应力腐蚀重要环节。文章基于室内腐蚀试验,利用超景深三维数字显微系统对预应力索体在不同腐蚀时间下的锈蚀损伤形貌进行了观测,采用蚀坑面积、深度、长轴长度等指标作为其表面腐蚀损伤的统计参数,通过函数描述了参数指标与时间的关系,分析了应力腐蚀的表观损伤演化规律;利用热场发射扫描电子显微镜对索体显微组织、裂纹萌生及其发展规律进行观测,从微观结构层面探求腐蚀损伤演化的力学本质。结果表明:在腐蚀介质环境中蚀坑长轴长度、面积随时间呈指数关系,平均腐蚀深度与时间呈幂函数关系,酸性腐蚀介质更有助于腐蚀坑槽的贯通;随腐蚀时间延长,预应力锚索试件的屈服和断裂荷载均逐渐减小,到达屈服点时试件所产生的位移也有所减小;随腐蚀时间延长,材料的塑性降低,脆性逐渐增强;酸性溶液中腐蚀时间较长的试件在拉伸破坏时易表现出应力腐蚀的特征。
Stress corrosion has become the principal factor that can affect the longterm durability of geotechnical pestressed anchorage cable.Based on indoor corrosion test, the appearance of rust damage of the prestressed cable under different corrosion time was accurately observed by using the super depth 3D digital microscope system. The parameters such as area, depth and long axis length of the corrosion pit were used as statistical parameters of the surface corrosion damage. The correlation function was used to describe the relationship between the above parameters and time in order to analyze the apparent damage evolution rule of stress corrosion.At the same time, Scanning Electron Microscopy was used to observe the microstructure of the cable and crack initiation and development rules, in order to explore the mesomechanical nature of corrosion damage evolution from the mesostructure level. The results show that the length of the long axis and the area of the etching pits grow exponentially with time in the environments of corrosive media. The average corrosion depth is a power function of time. The yield load and the fracture load of bar are gradually decreases, and when it arrives at the yield point bar displacement also decreases. The plasticity of the material decreases and the brittleness gradually increases with the extension of corrosion time. The specimens with long corrosion time in acid solution are prone to show the feature of stress corrosion when specimens are subjected to tensile failure test.
作者
张思峰
陈兴吉
韩冰
齐辉
Zhang Sifeng;Chen Xingji;Han Bing(School of Transportation Engineering,Shandong Jianzhu University,Jinan 250101,China;Qilu Transportation Development Group,Jinan 250101,China)
出处
《山东建筑大学学报》
2018年第6期1-6,14,共7页
Journal of Shandong Jianzhu University
基金
国家自然科学基金项目(41372300
51108252)
齐鲁交通发展集团有限公司科技计划项目(JHLYDKY3)
关键词
岩土预应力锚索
腐蚀损伤
演化机理
geotechnical prestressed anchorage cable
corrosion damage
evolution mechanism
