腐蚀环境下预应力锚筋损伤试验研究

发布时间：2018-04-10 02:15

本文选题：岩土工程　切入点：预应力　出处：《岩石力学与工程学报》2017年07期

【摘要】：为了深入研究腐蚀环境中锚固结构腐蚀损伤发展规律,考虑氧气浓度与局部腐蚀的影响,在室内开展腐蚀环境下预应力锚筋浸泡腐蚀试验及腐蚀试样材料力学性能试验。腐蚀试验过程中进行电化学测试与筋材局部应变监测,基于试验结果分析预应力、环境pH值、环境含氧浓度等因素与锚筋腐蚀速率、外观损伤特性、单位长度损失量、力学特性之间的关系,并探讨不同含氧环境下预应力锚筋局部应变发展规律。试验结果表明:(1)弱酸环境中酸性越强锚筋腐蚀速率越快;(2)氧气对预应力锚筋腐蚀促进作用显著,环境氧气浓度越高腐蚀速率越大,但超过一定值后增大现象不明显;(3)试验条件下,随着通氧速率增大,锚筋单位长度腐蚀量增加;(4)锚筋极限伸长率、极限抗拉载荷、弹性模量3个力学指标随着环境氧含量增大有明显的下降现象,且在同一通氧速率下,极限伸长率损失率最大,弹性模量损失率次之,而极限承载力损失率最小;(5)局部腐蚀使受腐蚀截面力心发生偏移,不同含氧环境下锚杆表面应变发展迥异,富氧侧应变呈拉应变增大趋势,而缺氧侧则由拉应变向压应变发展。
[Abstract]:In order to study the development of corrosion damage of Anchorage structure in corrosion environment, considering the influence of oxygen concentration and local corrosion, the corrosion test of pre-stressed anchor bars and mechanical properties of corrosion specimens were carried out indoors.Electrochemical test and local strain monitoring were carried out during corrosion test. Based on the test results, factors such as prestress, environmental pH value, environmental oxygen concentration and corrosion rate of anchor bars, appearance damage characteristics and unit length loss were analyzed.The relationship between mechanical properties and local strain development of prestressed anchor bars under different oxygen environment is discussed.The experimental results show that the stronger the acidity in the weak acid environment, the faster the corrosion rate of anchor bars is. The higher the oxygen concentration in the environment is, the higher the corrosion rate of prestressed anchor bars is, and the higher the oxygen concentration in the environment is, the higher the corrosion rate is.However, the increasing phenomenon is not obvious when the value exceeds a certain value. Under the experimental conditions, with the increase of oxygen flux rate, the corrosion amount per unit length of anchor bars increases, and the ultimate elongation rate and ultimate tensile load of anchor bars are increased.The three mechanical indexes of elastic modulus decreased obviously with the increase of environmental oxygen content, and under the same oxygen rate, the loss rate of ultimate elongation was the largest, and the loss rate of elastic modulus was the second.However, the local corrosion causes the force center of the corroded section to deviate. The strain on the surface of the anchor is different in different oxygen-containing environment, and the strain on the oxygen-enriched side increases with the tensile strain, while the anoxic side develops from the tensile strain to the compressive strain.
【作者单位】：长江科学院水利部岩土力学与工程重点实验室;广州白云国际机场股份有限公司;
【基金】：国家自然科学基金项目(41272350,51309025,41672320)~~
【分类号】：TV223

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