Effects of Loads and Erosion Dimensions on the Chloridion Transmission Rule in Concrete
钟小平 1许嘉豪 1刘洋 1夏晋 2朱炳喜 3张军 4倪克挺1
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作者信息
1. 扬州大学建筑科学与工程学院,江苏扬州 225127
2. 浙江大学结构工程研究所,杭州 310058
3. 江苏省水利科学研究院,江苏扬州 225002
4. 浙大宁波理工学院,浙江宁波 315100
折叠
摘要
为了研究荷载效应及侵蚀维度对混凝土中氯离子侵蚀特性的影响及其分析方法,对长期承受持续荷载的轴心受压、偏心受压及无应力构件进行一维及二维氯盐溶液干湿循环试验,分析不同荷载性质、不同侵蚀维度下自由氯离子含量的分布规律,结果表明:无应力状态下,相同侵蚀深度处,二维氯离子侵蚀浓度高于一维侵蚀浓度;轴向压荷载对氯离子的传输有抑制作用,在混凝土表层 0～40 mm 深度范围内,二维氯离子侵蚀浓度大于相同深度处一维侵蚀浓度,但小于无应力状态下一维侵蚀浓度;偏心拉应力对氯离子传输有加速作用,一维及二维侵蚀时,偏心受拉区氯离子的侵蚀程度均较偏心受压区严重;侵蚀面水平向上的区域侵蚀程度＞倾斜面＞向下的底面.将荷载效应对氯离子扩散性能的影响采用"等效表观氯离子扩散系数"来表征,并通过试验验证了其适用性;基于试验研究及理论分析,引入维度影响函数对Fick扩散模型进行修正,修正模型计算结果与实测二维氯离子侵蚀结果吻合较好,用修正模型来描述二维氯离子侵蚀特性是可行的.
Abstract
To study the effects of load and erosion dimension on the characteristics of chloride ion erosion in concrete and its analysis method,dry-wet cycle experiments of chloride salt solution were carried out on components under continuous loads for a long time,including axially compressed,eccentrically compressed,and stress-free components,in both one-dimensional and two-dimensional manners.The distribution of free chloride ion content under different load properties and erosion dimensions was analyzed.The results showed that under a stress-free condition,the two-dimensional chloride ion erosion concentration at the same erosion depth was higher than that of one-dimensional erosion;axial compressive load had an inhibitory effect on the transmission of chloride ions,within the 0-40 mm depth range of the concrete surface,the two-dimensional chloride ion erosion concentration was greater than that at the same depth of one-dimen-sional erosion,but less than the one-dimensional erosion concentration under a stress-free condition;eccen-tric tensile stress accelerated the transmission of chloride ions,during both one-dimensional and two-dimen-sional erosion,the degree of chloride ion erosion in the eccentric tension zone was more severe than in the eccentric compression zone;in terms of erosion degree,the area above the horizontal plane of the erosion face＞inclined plane＞bottom face downwards.The influence of load effects on the diffusive properties of chloride ions was characterized by the"equivalent apparent chloride ion diffusion coefficient",and its ap-plicability had been verified through experiments.Based on the experimental research and theoretical analy-sis,a dimension influence function was introduced to modify the Fick diffusion model.The modified mod-el's calculated results were in good agreement with the measured two-dimensional chloride ion erosion re-sults,indicating that it was feasible to describe the characteristics of two-dimensional chloride ion erosion using the modified model.
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