Kouřil Milan, Saksa Jan, Hybášek Vojtěch, Sedlářová Ivona, Němeček Jiří, Kohoutková Martina, Němeček Jiří
Department of Metals and Corrosion Engineering, University of Chemistry and Technology in Prague, Technická 5, 166 28 Prague, Czech Republic.
Department of Inorganic Technology, University of Chemistry and Technology in Prague, Technická 5, 166 28 Prague, Czech Republic.
Materials (Basel). 2025 Jul 17;18(14):3365. doi: 10.3390/ma18143365.
Electrochemical treatment by means of direct current (DC) is usually used as a measure for steel rebar corrosion protection, e.g., cathodic protection (CP), electrochemical chloride extraction (ECE), and re-alkalization (RA). However, the passage of an electrical charge through the pore system of concrete or mortar, coupled with the migration of ions, concentration changes, and resulting phase changes, may alter its chloride penetration resistance and, subsequently, the time until rebar corrosion activation. Porosity changes in hardened Portland cement mortar were studied by means of mercury intrusion porosimetry (MIP) and electrochemical impedance spectroscopy (EIS), and alterations in the mortar surface phase composition were observed by means of X-ray diffraction (XRD). In order to innovatively investigate the impact of DC treatment on the properties of the mortar-electrolyte interface, the cathode-facing mortar surface and the anode-facing mortar surface were analyzed separately. The corrosion of steel coupons embedded in DC-treated hardened mortar was monitored by means of the free corrosion potential (E) and polarization resistance (R). The results showed that the DC treatment affected the surface porosity of the hardened Portland cement mortar at the nanoscale. Up to two-thirds of the small pores (0.001-0.01 µm) were replaced by medium-sized pores (0.01-0.06 µm), which may be significant for chloride ingress. Although the porosity and phase composition alterations were confirmed using other techniques (EIS and XRD), corrosion tests revealed that they did not significantly affect the time until the corrosion activation of the steel coupons in the mortar.
通过直流电（DC）进行的电化学处理通常用作钢筋腐蚀防护的一种措施，例如阴极保护（CP）、电化学氯化物萃取（ECE）和再碱化（RA）。然而，电荷通过混凝土或砂浆的孔隙系统，再加上离子迁移、浓度变化以及由此产生的相变，可能会改变其抗氯化物渗透性，进而改变钢筋腐蚀激活前的时间。采用压汞法（MIP）和电化学阻抗谱（EIS）研究了硬化波特兰水泥砂浆的孔隙率变化，并通过X射线衍射（XRD）观察了砂浆表面相组成的变化。为了创新性地研究直流处理对砂浆 - 电解质界面性能的影响，分别对面向阴极的砂浆表面和面向阳极的砂浆表面进行了分析。通过自由腐蚀电位（E）和极化电阻（R）监测嵌入直流处理硬化砂浆中的钢试件的腐蚀情况。结果表明，直流处理在纳米尺度上影响了硬化波特兰水泥砂浆的表面孔隙率。高达三分之二的小孔（0.001 - 0.01 µm）被中等尺寸的孔（0.01 - 0.06 µm）所取代，这对于氯化物进入可能具有重要意义。尽管使用其他技术（EIS和XRD）证实了孔隙率和相组成的变化，但腐蚀试验表明，它们对砂浆中钢试件腐蚀激活前的时间没有显著影响。
