纳米SiO_(2)对混凝土耐蚀性能和溶蚀寿命的影响

Effect of Nano-SiO_(2) on Corrosion Resistance and Corrosion Life of Concrete

为研究纳米SiO_(2)对溶蚀混凝土损伤的影响,选取浓度为2 mol/L的NH 4Cl溶液为侵蚀介质,对普通混凝土和纳米SiO_(2)混凝土分别溶蚀0、4、9、28、45、64 d,测试了试件的抗压强度耐蚀系数.利用核磁共振(NMR)技术、场发射扫描电镜(SEM)和热分析仪研究了试样的组织结构.应用灰色系统理论建立了混凝土寿命GM(1,1)预测模型.结果表明:普通混凝土和纳米SiO_(2)混凝土的抗压强度均随溶蚀龄期的延长而不断降低;纳米SiO_(2)有效提高了混凝土在服役水环境条件下的结构可靠度,纳米SiO_(2)混凝土抗压强度耐蚀系数比普通混凝土高11.04%;纳米SiO_(2)可有效改善混凝土微结构缺陷,使微观结构更加致密,减缓了侵蚀介质在混凝土内部的扩散传输速率;通过GM(1,1)模型预测得到纳米SiO_(2)混凝土溶蚀寿命是普通混凝土的2.4倍.

In order to study the effect of nano-SiO_(2) on the damage of corrosion concrete,2 mol/L NH 4Cl solution was used as the erosion media to corrode ordinary concrete and nano-SiO_(2) concrete for 0,4,9,28,45,64 d respectively.The compressive strength corrosion resistant coefficient of the specimens were tested by hydraulic testing machine.The structures of the specimens were studied by nuclear magnetic resonance(NMR),field emission scanning electron microscopy(SEM)and thermal analysis.The GM(1,1)prediction model for concrete life was established using grey system theory.The results show that the compressive strength of ordinary concrete and nano-SiO_(2) concrete decreases with the age of corrosion;Nano-SiO_(2) effectively improves the structural reliability of concrete in service water environment,and the corrosion resistance coefficient of compressive strength of nano-SiO_(2) concrete is 11.04%higher than that of ordinary concrete;nano-SiO_(2) can effectively improve the microstructure defects of concrete,make the microstructure more compact,and slow down the diffusion and transmission rate of the corrosive medium inside the concrete;It is predicted by GM(1,1)model that the corrosion life of nano-SiO_(2) concrete is 2.4 times that of ordinary concrete.