煅烧水滑石对钢筋混凝土的阻锈机理研究

Corrosion inhibition mechanism of calcined layered double hydroxides on reinforced concrete

通过线性极化(LPR)、电化学阻抗谱(EIS)、能谱(EDS)、氯离子含量等测试,研究了氯盐-硫酸盐侵蚀下掺入水滑石(LDHs)、煅烧水滑石(CLDHs)对钢筋混凝土的阻锈作用。结果表明:CLDHs、LDHs具有较小的粒径、较大的比表面积,产生的微集料效应可以提高混凝土28 d抗压强度6%左右,并优化了混凝土孔隙结构,提高了混凝土体系氯离子结合率;耦合盐干湿循环侵蚀下,CLDHs和LDHs明显提高了钢筋混凝土内钢筋的极化电阻和容抗弧半径,CLDHs阻锈效率大于LDHs;随着循环次数的增加,阻锈效率下降,但干湿循环90次CLDHs的阻锈效率仍在85%以上,且阻锈机理主要来源于其对自由氯离子的吸附作用,因此,掺入CLDHs能够有效提高钢筋混凝土的抗锈蚀能力。

The corrosion inhibition effect of layered double hydroxides(LDHs)and calcined layered double hydroxides(CLDHs)on reinforced concrete under chloride-sulfate attack was studied by approaches of linear polarization resistance(LPR),electrochemical impedance spectroscopy(EIS),energy dispersive spectroscopy(EDS),and chloride ion content test.The results show that CLDHs and LDHs have small particle sizes and large specific surface areas,their micro-aggregate effect can improve the compressive strength of the concrete at 28 d by about 6%,optimize the pore structure of the concrete,and improve the chloride ion binding rate of the concrete system.Under coupled erosion of salt and drying-wetting cycles,CLDHs and LDHs can significantly increase the polarization resistance and capacitive arc of steel bars in reinforced concrete,and the corrosion inhibition efficiency of CLDHs is larger than that of LDHs.With the increase of the number of cycles,the corrosion inhibition efficiency decreases,but the corrosion inhibition efficiency of CLDHs is still above 85%after 90 drying-wetting cycles,and the corrosion inhibition mechanism is mainly originated from the adsorption effect of CLDHs on free chloride ions.Therefore,the addition of CLDHs can effectively improve the corrosion resistance of reinforced concrete.