干湿循环与受弯裂缝共同作用下海工砼梁内氯离子侵蚀及耐久性寿命预测  

Chloride Ion Erosion and Durability Life Prediction of Marine Concrete Beams under Combined Action of Dry-Wet Cycle and Flexural Cracks

作　　者：崔钊玮[1] 刘荣桂[1] 陆春华[1] 王豪杰 CUI Zhaowei;LIU Ronggui;LU Chunhua;WANG Haojie(Faculty of Civil Engineering and Mechanics,Jiangsu University,Zhenjiang 212013,China)

机构地区：[1]江苏大学土木工程与力学学院,镇江212013

出　　处：《硅酸盐通报》2020年第2期344-351,共8页Bulletin of the Chinese Ceramic Society

基　　金：国家自然科学基金(51778272,51878319)。

摘　　要：基于受弯裂缝对浪溅区海工混凝土内氯离子输运的影响分析,综合考虑混凝土损伤、混凝土结合氯离子能力、表层对流效应以及时间劣化效应等因素,建立了修正氯离子扩散模型。采用受弯开裂荷载与氯盐干湿循环共同作用试验来模拟浪溅区实际服役状态的海工混凝土梁内氯离子侵蚀过程,从而对上述模型进行验证。基于蒙特卡罗(Monte Carlo)方法,应用等效氯离子扩散系数的修正计算模型进行混凝土结构的耐久性寿命预测。研究结果表明,混凝土梁受弯开裂处的等效氯离子扩散系数与裂缝宽度、粉煤灰掺量呈指数函数关系。考虑海工混凝土结构的重要使命,将钢筋脱钝时间作为混凝土结构的耐久性极限,讨论了保护层厚度、粉煤灰掺量以及受弯裂缝宽度对混凝土结构耐久性寿命的影响,相关研究成果可为实际海工混凝土结构耐久性设计及寿命评估提供一定的借鉴。Based on the analysis of the influence of flexural cracks on chloride transport in marine concrete in the splash zone, a modified chloride diffusion model had been established considering concrete damage, chloride binding capacity of concrete, surface convection effect, time degradation effect and so on. In order to validate the above model, the combined action test of flexural cracking load and chloride cycling had been used to simulate the chloride ion erosion process in marine concrete beams in splash zone under actual service status. Based on Monte Carlo method, the modified calculation model of equivalent chloride diffusion coefficient was applied to predict the durability life of concrete structures. The results show that the equivalent chloride diffusion coefficient at the flexural crack of concrete beams is exponentially related to crack width and fly ash content. Considering the important mission of marine concrete structures, the initial corrosion time t0 of steel bar is taken as the durability limit of concrete structures. The influence of concrete cover thickness, fly ash content and flexural crack width on durability life of concrete structures has been predicted. The relevant research results can provide some reference for durability design and life evaluation of marine concrete structures.

关 键 词：海工混凝土 受弯裂缝 氯盐干湿循环 等效氯离子扩散系数 耐久性寿命预测 

分 类 号：TU375.1[建筑科学—结构工程]