盐度和浸润频率对混凝土中氯离子扩散的影响规律研究

Law of influence of salinity and infiltration frequency on the diffusion of chloride ions in concrete

模拟不同盐浓度海水、不同浸润频率,对标准成型混凝土试件进行海水室内侵蚀试验,测定氯离子含量。分别进行不同盐度下内部自由氯离子含量测定、表面氯离子含量曲线拟合及表面氯离子浓度经时规律研究;测定不同浸润频率下不同深度的自由氯离子含量,并分析研究表面氯离子浓度与不同浸润频率的关系。结果表明:混凝土内部自由氯离子含量随盐度增加、侵蚀时间增长而增大;混凝土表面氯离子浓度的经时演变规律满足幂指数模型,且幂指数参数随浸润频率的改变而有所不同;在一定龄期内,盐度对混凝土表面氯离子浓度的影响规律满足对数函数模型;当浸润频率较小时,混凝土氯离子渗透随频率增加而增大;当浸润频率增大至12次/d时,氯离子渗透速率减慢,混凝土内部自由氯离子含量降低。

Seawater with different salt concentration and different infiltration frequency were simulated to carry out seawater erosion test on standard formed concrete specimens and determine chloride ion content.The determination of internal free chloride ion content,fitting of surface chloride ion content curve,and study on the surface chloride ion concentration time rule were conducted under different salinity.The content of free chloride ions at different depths under different infiltration frequency was determined,and the relationship between surface chloride ion concentration and different infiltration frequency was analyzed and studied.The results show that the content of free chloride in concrete increases with the increase of salinity and erosion time.The temporal evolution of chloride ion concentration on concrete surface meets the power index model,and the power index parameter varies with the change of infiltration frequency.Within a certain age,the law of the influence of salinity on the chloride ion concentration on the concrete surface meets the logarithmic function model.When the infiltration frequency is low,the chloride ion penetration of concrete increases with the increase of the frequency.When the infiltration frequency is increased to 12 times/d the infiltration rate of chloride ions slows down and the content of free chloride ions in concrete decreases.