摘要
考虑钢筋锈蚀过程的长期积累效应及锈蚀产物沿钢筋周边的不均匀分布状况,提出了基于离散型锈胀模式的钢筋混凝土损伤时变数值计算模型。首先,把锈蚀过程中锈蚀产物向周围的扩散视为非规则形状随时间动态径向扩散,计算时将锈蚀产物沿环向离散为n个子区域,且每个子区域内锈胀体积的增加以位移增量形式等效,建立了考虑时变的离散型锈胀模型;其次,以非线性弹簧模拟锈胀产物对混凝土作用,混凝土采用弥散开裂模型,建立了钢筋混凝土锈胀损伤数值计算模型;最后,以不同保护层厚度及区域等工况,通过数值计算对钢筋锈蚀膨胀全过程中混凝土应力应变的变化规律及开裂时间进行了研究。结果表明,该模型对于钢筋混凝土中不均匀性锈胀损伤计算具有较好的适用性,能实现锈胀开裂时间的预测与评价,这对于混凝土结构后期使用维护与服役寿命预测具有重要的科研价值。
In consideration of long-term accumulative effect in process of steel bar corrosion and uneven distribution of rusted products along steel bar,variable value model when reinforced concrete is damaged is built based on disperse,rust and inflating model.First,the diffusion of rusted products in rusting process is as like radial diffusion of irregular shape with time increasing.When calculating,the rusted products is scattered as n subregions in circular directions,and in each subregion,the swelled volume adds as equally to displacement increment,the disperse,rust and swelled model is built;second,non-linear spring is used to simulate the effect of rust and swelled products on concrete which uses diffusing and cracking model,so rust and swell damaged numerical calculated model is built;finally,by the conditions of different thickness of protective layer and area,changing rule of stress-strain and cracking time of concrete is studied in process of rusting and swelling steel bar by numerical calculation.The result shows that this model has good applicability to uneven rust and swelling damage in reinforced concrete,and can predict and evaluate cracking time,offering important scientific significance for maintenance and predicting service life of concrete.
作者
郑佳
李忠
史立新
Zheng Jia;Li Zhong;Shi Lixin(School of Civil Engineering ,Lanzhou University of Technology ,Lanzhou 730050 ,Chin)
出处
《甘肃科学学报》
2018年第1期42-47,84,共7页
Journal of Gansu Sciences
基金
国家科学自然基金项目"西北侵蚀环境下隧道衬砌结构长期性能及服役寿命"
关键词
钢筋锈蚀
不均匀性锈胀
时变模型
Corrosion of steel bar
Uneven swell
Time varying model
