电化学修复过程混凝土内环境对钢筋表面析氢影响的实验研究

Effect of Concrete Inner Environment on Hydrogen Evolution of Rebar During Electrochemical Remediation

分析论证了动电位极化法测量混凝土中钢筋析氢电流密度的合理性,并测试了不同水灰比的混凝土试件中钢筋的析氢电流密度大小。结果表明,混凝土试件的水灰比越大,钢筋的析氢电流密度越小,析氢反应越容易发生,因此在电化学修复中对不同水灰比的混凝土结构不宜采用统一的析氢电流密度作为析氢控制条件。

Electrochemical remediation is one important method to improve the durability of the existed reinforced concrete structural parts. However, the hydrogen evolution during the reparative process restricts the applied range of electrochemical remediation. The Nernst formula indicated that the equilibrium potential of hydrogen evolution is related to reactant concentration,product concentration and temperature. Accordingly,the equilibrium potential of hydrogen evolution of rebar as a cathode during the electrochemical remediation is related to the inner environment of the concrete under repair. The rationality of measuring current density of hydrogen evolution by potentiodynamic polarization curve is demonstrated in this paper. Then the current density of hydrogen evolution of the rebar embedded in concretes with different water-cement ratio（W/C） is measured. Results indicate that the current density of hydrogen evolution is lower for the rebar embedded in the concrete with lower W/C ratio. Therefore, it is not suitable to adopt a common current density value as a specified index for the controlling of hydrogen evolution during the electrochemical remediation of different concretes.