有机酸对钢筋腐蚀和水泥浆体性能的影响

Influence of organic acids on the corrosion performance of reinforcement and material properties of cement paste

为了揭示有机酸粪污废水对钢筋混凝土构筑物材料性能和耐久性的影响,本文采用电化学方法和扫描电镜研究了浸没在含有不同体积分数有机酸的模拟混凝土孔溶液中的钢筋的电化学行为和表面形态,并采用X射线衍射仪和体视显微镜研究了模拟有机酸溶液对水泥净浆水化产物和微观结构的影响。研究结果表明:在模拟孔溶液中,不同体积分数的有机酸均能诱发钢筋腐蚀,经有机酸侵蚀后的钢筋腐蚀电位负移、腐蚀电流升高、腐蚀速度加快;且当模拟溶液中的有机酸体积分数越大时,钢筋的腐蚀速度越快。同时,XRD和表面分析试验结果表明,经有机酸侵蚀的水泥净浆基体,其中的氢氧化钙、硅酸二钙、钙矾石等组分被有机酸溶解,表面出现裂缝、分层和剥落,抗压强度下降。

In order to elucidate the influence of organic acids on the material properties and durability of reinforced concrete,electrochemical methods and scanning electron microscopy were used to investigate the electrochemical behavior and surface morphology of reinforcement immersed in simulated pore solutions containing organic acids with different volume fractions.X-ray diffraction and stereo microscope were used to evaluate the influence of organic acids on the hydration products and microstructure of cement paste.The results indicate that the corrosion potential of the reinforcement is negatively shifted and corrosion current density is significantly increased,and corrosion rate is accelerated in the presence of organic acids.Further more,a higher corrosion rate is related to a higher concentration of organic acids.Meanwhile,the component such as Ca（OH）2,dicalcium silicate and enttringite in cement paste is dissolved after erosion by organic acids,leading to the cracking,layering and spalling on the surfaces,and a decrease of compressive strength.