海水与腐蚀电流耦合作用下铝合金与混凝土界面黏结性能

Interfacial adhesion between aluminum alloy and reinforced concrete under coupling effect of chloride ion and corrosion current

为提高海洋混凝土结构的耐久性和使用性,基于牺牲阳极的阴极保护技术,对腐蚀防护与结构一体化的铝合金板-钢筋混凝土组合构件的界面黏结性能进行试验研究,建立海水环境与腐蚀电流耦合作用下界面黏结强度的计算方法。通过设计15组45个铝合金板与混凝土界面剪切试件,分别进行室内养护和耦合环境(海水环境与腐蚀电流)加速锈蚀,并进行单剪试验,研究黏结长度(60、80 mm和100 mm)、黏结宽度(60、80 mm和100 mm)、铝合金板表面刻槽深度(1.5 mm和2.5 mm)以及锈蚀时间(30、60 d和90 d)等参数对界面破坏形式、极限荷载及应变分布的影响。结果表明:室内环境养护下,试件的破坏形式为黏结层-混凝土之间的界面剥离,而耦合环境下试件的破坏形式转变为铝合金板与黏结层之间的界面剥离,且当锈蚀龄期达到90 d时,剥离的混凝土面积明显减少,故海水和腐蚀电流的耦合作用会降低铝合金板与黏结层界面的黏结性能;增大黏结长度、宽度以及表面刻槽深度,可提高室内环境下试件界面的极限破坏荷载,也能缓解耦合环境对试件界面黏结性能的不利影响;但黏结长度或宽度超过80 mm后,其缓解作用减弱。利用试验测试获得的极限荷载,拟合获得环境影响系数、槽深系数以及与试件黏结尺寸相关的系数,修正了Niedermeier黏结强度模型,可用于预测海水与腐蚀电流的耦合作用下铝合金板与混凝土界面的黏结强度。

In order to improve the durability and serviceability of marine concrete structures,a composite structure of aluminum alloy plate reinforced concrete integrating corrosion protection was proposed,based on the sacrificial anode cathodic protection technology.The interface bonding performance of the composite structure was studied,and a calculation method of interface bonding strength under the coupling action of seawater and corrosion current was established.15 sets(a total of 45)of aluminum alloy plate concrete interface shear specimens under indoor environment and coupling environment(seawater and corrosion current)with accelerated corrosion,were designed and single shear tests were carried out.The influences of parameters such as bond length(60mm,80mm and 100mm),bond width(60mm,80mm and 100mm),groove depth(1.5mm and 2.5mm)on the surface of aluminum alloy plate,as well as corrosion time(30 days,60 days and 90 days),on the failure mode,extreme load and strain distribution in specimen interface were explored.The results show that interface peeling between bonding layer and concrete is the failure mode under indoor curing,while interface peeling between aluminum alloy plate and bonding layer is the failure mode under coupling environment.As the corrosion time reaches 90 days,the peeling area of concrete decreases obviously,which indicates that the coupling action of seawater and corrosion current can reduce the interface bonding performance of the aluminum alloy plate and bonding layer.The increases of bonding length,width and surface groove depth can enhance the ultimate failure load of the specimen interface under indoor environments,and also alleviate the adverse impact of coupling environment on the bonding performance of the specimen.However,when the bonding length or width exceeds 80 mm,the above relieving effect is weakened.Using the ultimate load obtained from the experiment,the environmental impact coefficient,groove depth coefficient,and coefficients related to the bonding size of specimen were fitted.The Niedermeier bonding strength model was modified,which can be used to predict the bonding strength of aluminum alloy plate concrete interface under the coupling action of seawater and corrosion current.