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混凝土保护层对钢筋腐蚀机理及腐蚀速率的影响 总被引:1,自引:0,他引:1
混凝土保护层的厚度、电阻率和孔隙水饱和度对混凝土中钢筋的腐蚀机理及腐蚀速率具有重要影响。基于混凝土中钢筋宏电池腐蚀模型,定量分析了混凝土保护层的厚度、电阻率和孔隙水饱和度对钢筋腐蚀机理及腐蚀速率的影响。分析结果表明,混凝土保护层的电阻率和孔隙水饱和度对钢筋腐蚀的控制方式及腐蚀速率影响显著:当钢筋腐蚀受电阻控制时,钢筋腐蚀速率将随着混凝土保护层电阻率的增加而减小,随保护层厚度的增大而增大,但不受混凝土孔隙水饱和度的影响;当钢筋腐蚀受阴极控制时,钢筋腐蚀速率将随着混凝土保护层的孔隙水饱和度和厚度的增大而降低,但不受混凝土电阻率的影响。 相似文献
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结合理论分析、数值模拟和模型试验数据,分析了温度和相对湿度对混凝土中钢筋腐蚀控制模式及速率的影响规律.首先基于混凝土中钢筋腐蚀的电化学原理,并考虑电极反应的逆向反应速率对活化极化过电位的影响,改进了传统钢筋腐蚀宏电池模型中的阳极腐蚀电位;然后分析了温度和相对湿度对平衡电位、交换电流密度、极限电流密度等参数的影响,建立了能够有效考虑温度和相对湿度影响的钢筋腐蚀宏电池模型;最后利用人工和自然气候环境下的试验数据,对比验证了所建模型的有效性,并分析了温度和相对湿度对混凝土中钢筋腐蚀控制模式及速率的影响规律. 相似文献
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对腐蚀的发生机理和影响因素进行了概括,介绍了基于宏腐蚀原理开发的阳极梯系统的工作原理和评价体系;鉴于阳极梯系统难以捕捉到腐蚀发生时的微电流,运用法拉第第二定律计算钢筋锈蚀质量损失存在较大误差,因此采用干湿循环交替试验修正了混凝土开裂后锈蚀质量损失与宏电流的函数关系;根据苏通大桥索塔锚固区的实测数据,简要评估了当前索塔塔壁混凝土碳化程度和钢筋的腐蚀状态。结果表明:索塔锚固区混凝土不同深度的电位及电阻率变化较为稳定,腐蚀宏电流曲线相对平稳,宏电流极值远小于耦合电流的临界值15μA,锚固区混凝土的碳化速度缓慢,钢筋尚未发生腐蚀。研究结果可为相关桥梁结构腐蚀监测提供一定的参考。 相似文献
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《四川建筑科学研究》2017,(1)
建立了宏电池腐蚀回路,通过分析不同初始表面状态的钢筋在无氯盐试块和有氯盐试块中的腐蚀电位、微电池腐蚀速度、极化曲线和宏电池腐蚀速度,研究了钢筋初始表面状态对其腐蚀行为的影响。结果表明,与全裸抛光表面相比,原氧化皮表面或初始锈蚀表面对改善钢筋的腐蚀电位起积极作用。锈蚀表面钢筋的微电池腐蚀速度较大且随着初始锈蚀程度的增加而增大。与初始锈蚀表面相比,原氧化皮表面能削弱钢筋的微电池腐蚀,但对其宏电池腐蚀有不利的影响。 相似文献
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一种预测混凝土氯离子扩散系数的方法 总被引:4,自引:0,他引:4
混凝土的氯离子扩散系数是预测混凝土中钢筋锈蚀及结构耐久性的重要参数。介绍了一种由混凝土组成材料预测其氯离子扩散系数的经验计算公式 ,指出应用中注意的问题 ,并讨论了主要影响因素 相似文献
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混凝土中钢筋腐蚀速度的过程控制 总被引:10,自引:0,他引:10
在总结国内外混凝土中钢筋腐蚀试验研究最新资料的基础上 ,对钢筋表面脱钝后腐蚀的主要过程进行了机理分析 ,同时阐述了其控制腐蚀速度的具体条件。 相似文献
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The paper includes automated modeling and experimental verification of corrosion in reinforced concrete construction under the effect of varying oxygen concentration. Various construction corrosion cells with different concrete compositions under four different environmental conditions (air dry, submerged, 95% R.H and alternate wetting-drying) have been investigated under controlled laboratory conditions. Using the results (half-cell potential and gravimetric corrosion mass loss) of these laboratory tests and an automated computer-aided simulation model based on mass and energy transfer through the porous construction media for the corrosion process, it was possible to predict, maintain and manage the influence of oxygen concentration on the corrosion rate of the reinforcement in concrete construction under various defined conditions satisfactorily. The variation in oxygen concentration available for corrosion reaction has been taken into account simulating the actual construction field conditions such as by varying concrete cover depth, relative humidity, water-cement ratio, etc. The modeling task has been incorporated by the use of an automated computer based construction durability model ‘DuCOM’ developed by our construction research group at The University of Tokyo as a finite element computational approach for the effect of oxygen on corrosion in relation to W/C, concrete cover, chloride concentration and various environmental humidity construction conditions. This paper is of interest to a broad readership for those interested in automation in reinforced concrete construction involving durability design & engineering related to corrosion of steel in concrete, corrosion resistant construction technology, corrosion maintenance & management. The scope of this paper encompasses various stages of the corrosion in construction life cycle from initial planning and design, through construction of steel reinforced concrete facility, its operation and maintenance, to the estimation of demolishing due to limiting oxygen controlled corrosion damage. This paper contains novel investigations involving computer-aided durability design, corrosion modeling under varying oxygen, classification and standardization of corrosion product data. The paper incorporates mass and energy process simulation models and graphics for the effect of oxygen on corrosion and its automated inspection as well as management. This comprehensive automated modeling and experimental investigation involving variety of materials and environmental variables will help in profound understanding, maintenance and management of oxygen controlled corrosion reaction in RC construction and will provide significant future research prospects in the field of oxygen limiting automated corrosion modeling of RC construction. 相似文献
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化工大气环境中混凝土的腐蚀机理及性能研究 总被引:3,自引:0,他引:3
采用二氧化硫来模拟工业大气对混凝土进行加速腐蚀试验 ,研究了混凝土在化工大气环境中的腐蚀机理和性能以及相应的影响因素。 相似文献
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Corrosion of steel in concrete is one of the major causes of premature deterioration of reinforced concrete structures, leading to structural failure. Various methods are being used to extend the service life of reinforced concrete structures, which include surface coatings to concrete surface, coatings to the reinforcement, cathodic protection, chloride removal and corrosion inhibitors. Of these methods, the use of corrosion inhibitors is found to be one of the effective methods to control rebar corrosion. An attempt has been made to study the performance of the anodic inhibitors (sodium nitrite and zinc oxide), cathodic inhibitors (mono ethanol amine, diethanol amine and tri ethanol amine) and mixed inhibitors to control rebar corrosion. Compressive strength test, tensile strength test, chloride diffusion test and macro cell corrosion test were conducted by varying the type of inhibitors and varying the concentration of inhibitors. The addition of inhibitors not only increased the compressive strength of the concrete but also improved the corrosion resistance properties. 相似文献
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绿色高性能混凝土性能研究 总被引:3,自引:1,他引:2
研究了一种由固体碱为激发剂制备的碱 -矿渣 -高钙粉煤灰渣新型胶凝材料配制的绿色高性能混凝土的渗透性、碱集料反应、工作性与抗压强度。结果表明 :该混凝土具有良好的抗Cl- 渗透的能力 ,不会产生膨胀性破坏的碱集料反应 ,矿渣与粉煤灰渣的质量比、水胶比、减水剂的掺量及粗骨料的种类对绿色高性能混凝土的工作性和强度有明显的影响 ,为混凝土的可持续发展指明了一条新途径。 相似文献
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