混凝土中钢筋腐蚀破坏的研究概况

综合讨论了混凝土中钢筋腐蚀的机理、影响及其电化学检测方法。通过分析提出了混凝土中钢筋腐蚀研究的难点以及今后的重点研究方向。     

混凝土结构中钢筋的腐蚀与防护

混凝土结构中钢筋的腐蚀行为对结构的耐久性具有很大的影响.分析了钢筋腐蚀的原因和合理选择腐蚀防护措施的重要性以及混凝土结构中钢筋腐蚀的机理、腐蚀过程及其影响因素.提出了混凝土结构中钢筋的腐蚀防护措施.     

含氯混凝土中钢筋宏电池腐蚀的研究

为了确定含氯混凝土中钢筋的宏电池腐蚀的特性,研究了钢筋腐蚀速度与混凝土电阻间的关系。在宏电池阴阳极之间串联可变电阻来模拟混凝土电阻的变化。实验结果显示钢筋腐蚀反应的自然腐蚀电位主要为阳极反应决定,而腐蚀反应速度为阴极反应控制。混凝土电阻对钢筋腐蚀反应速度影响很大。     

含氯混凝土中钢筋宏电池腐蚀的研究

为了确定含氯混凝土中钢筋的宏电池腐蚀的特性 ,研究了钢筋腐蚀速度与混凝土电阻间的关系。在宏电池阴阳极之间串联可变电阻来模拟混凝土电阻的变化。实验结果显示钢筋腐蚀反应的自然腐蚀电位主要为阳极反应决定 ,而腐蚀反应速度为阴极反应控制。混凝土电阻对钢筋腐蚀反应速度影响很大。     

混凝土中钢筋腐蚀的测定与评价方法

综述了混凝土中钢筋腐蚀的测定与评价方法,包括腐蚀面积率、失重率、断面缩减率、自然电位、线性极化电阻、交流阻抗谱(EIS)、腐蚀电流、混凝土比电阻和四极法等,介绍了各种方法的特点与应用过程中存在的问题,以及国内外的研究现状.研究认为,评价混凝土中钢筋腐蚀应选择合理的测定与评价方法,四极法可以在不破坏混凝土结构的情况下监控混凝土中钢筋锈蚀过程,是未来研究的热点之一.     

镁水泥混凝土中钢筋的电化学腐蚀研究

为解决分布在西部盐湖地区出现的煤矿矿区钢材腐蚀问题,结合煤矿矿区实际环境,采用实验、理论分析等方法研究了镁水泥混凝土中钢筋的腐蚀.采用CS350电化学工作站,研究镁水泥混凝土中钢筋的电化学腐蚀,结合SEM微观实验和EDS元素扫描结果,对镁水泥混凝土中裸露钢筋腐蚀状况进行描述.研究表明:美加力涂层钢筋状态良好,未出现腐蚀状态;锌美特涂层钢筋出现了低腐蚀现象;而裸露钢筋表面出现了严重腐蚀.钢筋涂层防腐蚀性美加力涂层较好,锌美特涂层次之;涂层钢筋虽然防腐效果不同,但对裸露钢筋的防腐蚀性能有明显有利影响.     

用电阻探针法研究水环境中钢筋混凝土的腐蚀行为

混凝土中钢筋腐蚀十分严重,为了对混凝土内钢筋腐蚀进行在线监测,设计了箔栅电阻探针试样及钢筋腐蚀监测仪.介绍了电阻探针监测系统的原理及组成,采用电阻探针法测量了10 mm和20 mm两种混凝土保护层厚度的试样浸泡在青岛海水全浸区、潮差区和长江港淡水环境以及实验室内3%氯化钠溶液中的钢丝电阻腐蚀情况,由电阻值变化可计算出钢丝腐蚀率.试验结果表明,电阻探针法能实时地监测混凝土中钢筋腐蚀的行为.     

全固态参比电极的制备及其在钢筋腐蚀监测中的应用

钢混结构中钢筋的腐蚀是影响结构耐久性的重要因素，腐蚀可以造成钢筋本身力学性能以及钢筋与混凝土粘结性能的劣化，这将严重影响钢混结构的承载力及服役寿命。基于电化学方法进行腐蚀监测的腐蚀传感器中通常需要应用参比电极为监测方法提供研究电极的电位，然而传统的参比电极由于其使用寿命有限从而限制了其在实际工程中的应用。制备了一种新的能够满足混凝土中钢筋腐蚀监测用的全固态参比电极。在水泥砂浆中应用动电位扫描的方法对钢筋的腐蚀进行了研究．研究结果表明，ASSRE的电位稳定，应用全固态参比电极能够得到理想的动电位扫描曲线。     

混凝土中钢筋腐蚀与钢筋阻锈剂

钢筋腐蚀是影响混凝土结构耐久性的最重要因素。本文综述了混凝土中钢筋的腐蚀机理、钢筋阻锈剂的作用机理,分析了钢筋阻锈剂的发展现状,认为采用钢筋阻锈剂是防治混凝土内钢筋腐蚀的有效、经济、实用的方法。     

萘系减水剂对硬化水泥浆体及孔隙液中钢筋腐蚀的影响

为了研究外加剂对混凝土中钢筋腐蚀的影响,模拟了混凝土孔隙液及制备了硬化水泥浆体,研究了添加不同含量的萘系减水剂对钢筋腐蚀的影响.结果表明:在模拟混凝土孔隙液中加入萘系减水剂对钢筋腐蚀有轻微的促进作用,当减水剂含量达到一定值时腐蚀增大的趋势就会消失;在硬化水泥浆体中加入萘系减水剂可以减缓钢筋的腐蚀,添加0.5%萘系减水剂阻锈效果最明显,且随着时间的延长,萘系减水剂对硬化水泥浆体中钢筋的阻锈效果增加;加入减水剂增强了硬化水泥浆体的密实性,从而减缓了钢筋的腐蚀.     

Seismic flexural behavior of concrete connections reinforced with CFRP bars and grids

The corrosion of steel reinforcement in concrete and the resulting deterioration of structures prompted research on fiber reinforced polymers (FRP) as potential reinforcement for concrete members, for use in new construction. FRPs have more favorable advantages for new concrete buildings subjected to seismic loads particularly in corrosive environment.     

纤维增强聚合物基复合材料加固锈蚀钢筋混凝土圆柱轴心受压性能

为了给纤维增强聚合物基复合材料（FRP）加固腐蚀环境下钢筋混凝土圆柱的设计和施工提供参考,促进FRP加固钢筋混凝土圆柱的应用,本文通过加速腐蚀得到类似实际环境中已锈损钢筋混凝土圆柱,采用碳纤维增强聚合物基复合材料（CFRP）条带和玻璃纤维增强聚合物基复合材料（GFRP）条带分别对锈蚀钢筋混凝土圆柱进行加固,最后对加固后圆柱进行轴心受压试验,重点研究钢筋锈蚀率、FRP层数和种类对钢筋混凝土圆柱受压承载力的影响;基于对FRP条带间隔约束效应、钢筋锈蚀对混凝土截面及钢筋力学性能影响的研究与分析,提出FRP条带间隔约束锈蚀钢筋混凝土圆柱轴心受压承载力计算模型。试验实测值与模型计算值之比的平均值为1.020,变异系数为0.063,二者符合较好。     

Electrochemical noise technique for the prediction of corrosion rate of steel in concrete

A research programme was undertaken to examine the limitations and applicability of the Electrochemical Noise Technique (ECN) for the determination of corrosion rates of steel reinforcement. The measurements were made on full-scale reinforced concrete beams under cyclic and static loading and exposed to a corrosive environment. Results from short and long-term tests suggest, rather surprisingly, that for a given test condition equal accuracy in predicting the corrosion rate can be obtained from the standard deviation of the potential noise and the electrode potential. There are indications, however, that valuable qualitative information about the state of corrosion may be obtained by means of potential trace.     

Determination of the residual longevity of reinforced concrete beam members on the basis of fracture mechanics

We propose a method for prediction of the residual longevity of reinforced concrete beam structural members based on fracture mechanics. We derive analytic relations, analyze them, and compare the results obtained with experimental data and results of calculations according to normative documents. We also develop a model of corrosion degradation, allowing one to estimate the residual service life of reinforced concrete structures in corrosive environments. Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 35, No. 5, pp. 83–90, September–October, 1999.     

受腐蚀钢筋混凝土构件破坏过程的分形行为

本文根据试验资料,分析了受腐蚀钢筋混凝土构件在荷载作用下开裂及裂纹的演化、分布特性,证明了受腐蚀钢筋混凝土构件表面裂缝具有分形特征。利用分形几何学研究受腐蚀钢筋混凝土构件开裂及破坏过程,讨论了受腐蚀钢筋混凝土构件表面裂缝的分维数与构件中混凝土及钢筋的腐蚀损伤程度之间的关系及其延性系数降低量之间的关系。研究表明该分维数可作为构件受腐蚀程度的衡量指标,并可用来评估不同腐蚀程度钢筋混凝土构件的力学性能,从而为受腐蚀钢筋混凝土构件的剩余寿命评价提供了一个新的途径,为受腐蚀钢筋混凝土结构的承载力研究建立了一定的理论基础。     

Effect of Reinforcement Corrosion Sediment Distribution Characteristics on Concrete Damage Behavior

Reinforcement corrosion directly affects the mechanical behavior of reinforced concrete structures. An electric corrosion test was conducted on a reinforced concrete test specimen, and a finite element model of the reinforcement corrosion damage was established. In addition, the damage behavior of reinforced concrete under different corrosion sediment distribution characteristics and different corrosion rates was studied. It was noted that when corrosion sediments are in a “semiellipse+semicircle” distribution, the results of numerical calculation are consistent with those obtained experimentally, reflecting the damage characteristics of reinforced concrete test specimens. Further, the results showed that the distribution characteristics of corrosion sediments greatly influence the damage behavior of reinforced concrete. In particular, when the corrosion sediments demonstrate a “semiellipse” distribution, reinforced concrete members may easily suffer from reinforcement damages. In the case of “semiellipse+semicircle” and “circle” distributions, the cohesive force between the reinforcements and concrete decreases: With the same corrosion rate, the damaged area expands with the increase in the number of reinforcements, which indicates a reduction in the cohesive force and thus, a reduction in the damage in the reinforcement area. This paper analyzes in-depth the effects of reinforcement corrosion expansion on the concrete damage behavior, provides references for practical engineering.     

硫酸盐环境中CFRP约束劣化混凝土柱的力学性能

为研究碳纤维增强树脂复合材料(CFRP)加固经硫酸盐腐蚀劣化后混凝土柱的力学性能,构建CFRP约束劣化混凝土的力学模型,采用CFRP约束普通混凝土后腐蚀和CFRP约束劣化混凝土两种工况进行试验,在试验研究基础上,引入损伤率及强度保持率作为损伤的量化指标,建立两者之间的关系;通过对CFRP约束混凝土强度及应变规律的回归分析,建立适用于硫酸盐环境下CFRP约束劣化混凝土的极限强度、应变模型及应力-应变关系模型。结果表明:随侵蚀时间增长,两种工况下CFRP约束混凝土极限强度和应变的变化规律及劣化速度均不同。预劣化的混凝土柱虽然进行了表面处理,但内部已经存在损伤,在侵蚀环境中采用CFRP加固混凝土柱时,应该考虑混凝土初始损伤的影响。      

厦门翔安海底隧道钢筋腐蚀监测技术

海底隧道由于其特殊及地质环境的复杂性,为保证海底隧道钢筋混凝土的耐久性与结构服役能力,对其腐蚀状态进行监测尤为迫切。该文研究了翔安隧道钢筋腐蚀监测系统的设计,包括商用的以及基于电化学和物理方法的自主研发的腐蚀传感器,腐蚀监测断面与测点的布置、腐蚀传感器的安装,以及腐蚀数据库的建立。通过现场采集的腐蚀监测数据,评价了翔安海底隧道目前的腐蚀状况。最后介绍了基于超声导波的钢筋腐蚀监测研究新进展。     

混凝土设计参数对氯盐环境下钢筋锈蚀的影响研究

研究了混凝土设计参数包括水胶比、胶凝材料组成、保护层厚度和混凝土氯离子含量等对氯盐环境下混凝土中钢筋锈蚀的影响。通过模拟氯盐环境下混凝土中钢筋所处的锈蚀环境,并以一定的方法加速混凝土中钢筋的锈蚀,采用电化学测试手段(钢筋腐蚀电位和钢筋腐蚀电流密度)来评价各设计参数对钢筋锈蚀的影响。结果表明,水胶比越小、保护层厚度越大、混凝土氯离子含量越小、使用矿物掺合料能有效延缓钢筋开始锈蚀时间,并在不同程度上减小钢筋的锈蚀速率。试件在试验一段时间后被破损,将钢筋周围砂浆制样并进行SEM扫描电镜元素分析试验,进一步验证电化学测试方法的准确性及钢筋的锈蚀程度。     

Effect of ground granulate blast-furnace slag on corrosion performance of steel embedded in concrete

Corrosion of steel in concrete is one of the major causes of premature deterioration of reinforced concrete structures, leading to structural failure. To prevent the failure of concrete structures because of corrosion, impermeable and high performance concretes should be produced various mineral admixtures. In this study, plain and reinforced concrete members are produced with mineral admixtures replacing cement. Ground granulated blast-furnace slag (GGBFS) has replaced cement as mineral admixture at the ratios of 0%, 25% and 50%. The related tests have been conducted at the ages of 28 and 90, after exposing these produced plain and reinforced concrete members to two different curing conditions. The unit weight, ultrasonic pulse velocity, splitting tensile and compressive strength tests are conducted on plain concrete members. Half-cell potential and accelerated corrosion tests are also conducted on reinforced concrete members. According to the test results, it is concluded that the curing age and type are important and corrosion resistant concrete can be produced by using GGBFS mineral admixture at the ratio of 25%.