共查询到19条相似文献,搜索用时 125 毫秒
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浇注了5个钢筋混凝土柱式大试件,养护三个月后通过电化学方法加速其锈蚀,得出了锈胀开裂时钢筋的锈蚀率。基于电化学锈蚀试验结果,并结合已有的试验资料,建立了考虑电化学锈蚀速度、相对保护层厚度及粗钢筋影响的锈裂模型,该模型具有较强的通用性。 相似文献
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根据电化学测试基本原理,对混凝土中钢筋的锈蚀进行了试验研究,提出了电化学综合检测方法及钢筋锈蚀速率和钢筋剩余使用寿命的辅助模型,建立了混凝土中钢筋锈蚀状况的评估体系。 相似文献
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锈蚀钢筋混凝土梁抗弯强度的试验研究 总被引:50,自引:0,他引:50
通过电化学腐蚀的方法进行了锈蚀钢筋混凝土梁抗弯强度的试验研究。根据试验数据 ,拟合出了钢筋锈蚀率对钢筋混凝土梁中钢筋与混凝土协同工作系数的影响公式。还给出了锈蚀钢筋混凝土梁抗弯强度的表达式及其简化式。其结果有益于完善和发展锈蚀钢筋混凝土梁的计算方法。 相似文献
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混凝土中钢筋加速锈蚀试验适用性研究 总被引:2,自引:0,他引:2
钢筋锈蚀导致其屈服强度降低、力学行为改变,影响钢筋与混凝土之间的粘结性能,钢筋锈蚀量影响钢筋混凝土的失效模式。为研究锈蚀钢筋混凝土结构的相关性能,需要在较短时间内得到所需的锈蚀构件。通过对4种不同工况下混凝土中钢筋电化学加速锈蚀方法进行对比试验,得到了锈蚀后钢筋表面形态特征,分析了模拟自然环境条件下钢筋锈蚀的适用性。试验表明:全浸泡外加电流加速锈蚀方法使钢筋纵向、径向表面形成均匀锈蚀,而自然环境锈蚀钢筋表面锈蚀相对不均匀,坑蚀更明显,两者差异显著;利用全浸泡外加电流加速锈蚀方法进行锈蚀钢筋与混凝土粘结-滑移本构关系和锈蚀钢筋混凝土构件承载能力等研究不合适;半浸泡和贴面外加电流加速锈蚀方法能较好模拟自然环境锈蚀;加速锈蚀试验方法的理论锈蚀质量高于试验锈蚀质量。图12表1参7 相似文献
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利用电化学锈蚀试验,得出了锈胀开裂时钢筋的锈蚀率.对现有锈裂模型及试验资料综合分析,并结合试验结果,建立了考虑电化学锈蚀速度、相对保护层厚度及粗钢筋影响的锈裂模型. 相似文献
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The performance of concrete specimens reinforced with uncoated rebars or rebars coated with inorganic conversion coatings was investigated. The corrosion resistance of rebars and the bond strength at the rebar/concrete interface for uncoated rebars as well as rebars coated with three different inorganic conversion coatings were evaluated according to the corresponding ASTM G109 standard. The results showed that different inorganic conversion coatings give significant enhancements of corrosion resistance and increased interface bond strength compared to uncoated ordinary steel rebars. However the extent to which each conversion coating improves the corrosion resistance of the rebars and the interface bond strength inevitably depends on the chemical composition of the applied inorganic conversion coating. 相似文献
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M.P. Papadopoulos C.A. Apostolopoulos A.D. Zervaki G.N. Haidemenopoulos 《Construction and Building Materials》2011,25(8):3367-3374
In a large number of steel reinforced concrete buildings in Greece, spalling of the cement has left the steel reinforcement (rebars) exposed to the atmosphere. This has led to corrosion of the exposed rebars, especially in coastal areas, with questions regarding their remaining load-carrying capacity. This work addresses the problem of corrosion and strength degradation of such exposed rebars. A large number of samples (sections of exposed rebars) were collected from buildings up to 96 years old, and weight loss measurements, tensile testing and fractographic analysis were carried out. Accelerated corrosion testing (salt spray) was performed on new similar grade rebars in order to establish a correlation with the naturally corroded exposed rebars.It was found that exposed rebars suffer from uniform corrosion followed by degradation of mechanical properties. In certain cases the properties were below the minimum threshold required by the international standards. A rough estimate of the correlation factor between natural corrosion of exposed rebars and salt spray corrosion has been derived. This correlation factor could be used, under certain limitations, to estimate the condition, in terms of mechanical property degradation and structural integrity, of coastal buildings with exposed rebars in Greece. 相似文献
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参照ACI 440.3R-04提供的试验方法,将90根玻璃纤维增强塑料(GFRP)筋分别放入40℃、60℃和80℃的模拟混凝土溶液中进行加速老化试验,侵蚀时间分别为3.65 d、18.0 d、36.5 d、92.0 d和183.0 d,分析了温度、侵蚀时间、SiO2含量等参数对GFRP筋受压力学性能的影响。研究表明:侵蚀183.0 d后,40℃、60℃、80℃模拟混凝土环境下的GFRP筋抗压强度较侵蚀前分别下降了29.59%、39.12%和47.62%,其抗压弹性模量分别下降了10.12%、12.47%和19.06%。采用扫描电子显微镜(SEM)对侵蚀前后GFRP筋的微观形貌进行了观测,发现侵蚀后GFRP筋的劣化区域内纤维与周围树脂之间出现了明显的脱粘现象,而且随着温度的提高这种脱黏现象更加明显。采用X射线荧光光谱分析仪(XRF)分析了侵蚀前后GFRP筋的SiO2含量变化,结果表明随着侵蚀时间的增加,模拟混凝土环境下GFRP筋中SiO2含量呈递减趋势;侵蚀前GFRP筋中SiO2含量为62.11%,在40℃、60℃和80℃模拟混凝土环境下侵蚀183.0 d后,GFRP筋中SiO2含量较侵蚀前分别下降到52.05%、50.66%和47.65%。基于XRF分析提出了模拟混凝土环境下GFRP筋抗压强度的预测模型。 相似文献
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海水浪溅下混凝土中锈蚀钢筋性能试验研究及仿真分析 总被引:7,自引:3,他引:7
75根海水浪溅环境下混凝土中I级和II级锈蚀钢筋的拉伸试验表明 :要考虑由于锈坑引起的应力集中对强度的影响。讨论了屈服强度、极限强度、极限伸长率和破坏形式与重量锈蚀率的关系 ,分析了钢筋的应力应变关系和极限强度与屈服强度比值随锈蚀率提高的变化规律。海水浪溅环境比大气环境下的锈蚀钢筋承载能力低 15 %左右 ,截面损失率与重量损失率的差异要小。锈蚀钢筋有限元仿真分析表明 :锈坑引起的应力集中使屈服荷载比仅考虑面积减小的计算荷载低 5 0 %左右 ;初始直径越大 ,锈坑对强度的影响越小 ;锈坑形状和宽度对强度的影响不明显。数据存在一定离散性 ,对可能原因进行了分析。 相似文献
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Corrosion behavior of epoxy/zinc duplex coated rebar embedded in concrete in ocean environment 总被引:2,自引:0,他引:2
ShiGang Dong Bing ZhaoChangJian Lin RongGui DuRongGang Hu Gregory Xiaoge Zhang 《Construction and Building Materials》2012,28(1):72-78
The corrosion behavior of epoxy/zinc duplex coated rebar embedded in concrete is evaluated comparing with the black steel, galvanized and epoxy coated rebars for a long term in ocean environment. The effect of mechanical damages of epoxy coatings on the corrosion protection is examined. The epoxy coated and epoxy/zinc duplex coated rebars show the higher anti-corrosion performance than other types of rebars. However, once the epoxy coating is mechanically damaged, the more serious corrosion may occur in the damaged area of epoxy coated rebar in concrete. The epoxy/zinc duplex coating remains a good corrosion protection to steel in concrete even when suffering from some mechanical damages. 相似文献
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An integrated and cost-effective sensor system to monitor the state of reinforced concrete structures from the corrosion point of view was developed. The sensor provides measurements of the open circuit potential of rebars, the corrosion current density of rebars, the electrical resistivity of concrete, the availability of oxygen, the chloride ions concentration in concrete, and the temperature inside the structure. The integrated system consists of different electrodes embedded in concrete and a software system that acquires and analyses the data. The results obtained so far show the capabilities of this type of sensor to determine the corrosion state of existing as well as new concrete structures. 相似文献
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护环法在钢筋混凝土体系腐蚀评价中的可行性研究 总被引:1,自引:0,他引:1
采用普通三电极体系评价现场大钢筋混凝土结构时。辅助电极面积与钢筋表面积相差很大而导致极化电力线难以均匀分布在钢筋表面,极化面积不确定。为解决这一问题,采用护环电极(Guard Ring Electrode,GRE or GE)方法即在普通三电极法基础上添加一圆环形护环电极(GE).通过GE电流将辅助电极(CE)电流限制在CE投影面积内,试验中评价了不同腐蚀状态的钢筋。并与均匀极化法对比,结果表明:在正确的电流限制下。护环电极法能够较准确地评价钢筋腐蚀状态,该方法尤其适合已脱钝体系。 相似文献