Q235钢/导电混凝土在3种典型土壤环境中腐蚀的灰色关联度分析

采用动电位扫描和电化学阻抗谱(EIS)技术,研究了Q235钢/导电混凝土在盐碱土、黄棕壤、红壤中的腐蚀行为,分析了土壤环境因素对腐蚀过程的影响规律,并基于灰色关联度理论计算了土壤中各离子对导电混凝土中Q235钢腐蚀过程的影响权重。结果表明,加速腐蚀45 d后,Q235钢/导电混凝土表面出现孔洞、边缘出现细微裂纹。Q235钢/导电混凝土在3种典型土壤环境中腐蚀速率按土壤类型由小到大排序为:盐碱土<黄棕壤<红壤。灰色关联度计算结果表明,Q235钢/导电混凝土在土壤中腐蚀时,土壤中各离子影响权重排序为:pH>SO₄^2-]>Ca²⁺]>Cl^-]>HCO₃^-]>Mg²⁺]>Fe3+]。随着土壤环境pH的降低,导电混凝土劣化程度增大,腐蚀速率上升。土壤中的H⁺、SO₄^2-会直接与导电混凝土组分发生反应,导致混凝土劣化,其影响权重最大。而Ca²⁺需通过扩散的方式进入导电混凝土孔隙液,以析出相应的氧化物或者碳酸盐沉积的方式提供物理防护作用,其影响权重略低。其中,由于Cl^-对Q235钢腐蚀的促进过程受到混凝土层及双电层隔绝作用的抑制,其影响权重较低。

Gray Correlative Degree Analysis of Q235 Steel/conductive Concrete Corrosion in Three Typical Soil Environments

The corrosion behavior of Q235 steel/conducting concrete in saline-alkali soil,yellowbrown soil,and red soil respectively was studied by means of potentiostatic scanning and electrochemical impedance spectroscopy(EIS)techniques,so that to reveal the influence of soil environmental factors on the corrosion process.Based on the grey correlation theory,the influence weight of each ion in soils on the corrosion process of Q235 steel in conductive concrete was calculated.The results show that after 45 d of accelerated corrosion,holes and fine cracks appeared on the surface of Q235 steel/conducting concrete.The corrosion rate of Q235 steel/conducting concrete in three typical soil environments may be ranked from small to large according to soil type:saline-alkali soil,yellow-brown soil,and red soil.The calculation results of the grey correlation degree show that when the Q235 steel/conducting concrete is cor-roded in the soil,the weighting of soil environmental factors may be ranked as follows:pH>SO₄^2-]>Ca²⁺]>Cl^-]>HCO₃^-]>Mg²⁺]>Fe³⁺].As the pH of the soil environment decreases,the degradation degree of conductive concrete increases,while the corrosion rate increases.H+and SO₄^2-in the soil will directly react with conductive concrete components,resulting in concrete degradation,which has the greatest impact weight.Ca²⁺can migrate inward to the conductive concrete pore fluid,therewith leading the precipitation of relevant oxides or carbonates there,which act as physical protective means,hence the impact weight of Ca²⁺is slightly lower.The influence of Cl^-on the corrosion of Q235 steel is inhibited by the insulation effect of the concrete layer and the electric double layer,so the influence weight is also lower.