The 4th Asian Concrete Federation Symposium on Emerging Technologies for Structural Longevity (ACF2023- ETSL)

90 / 2022-04-18 04:17:53

Reactive-transport numerical model in reinforced concrete structures with chloride attack and the active electric field corrosion control

chloride attack, reactive transport，active electric corrosion control

Chloride-induced steel corrosion is one of the primary factors to cause the deterioration of those RC structures located in the coastal environment. The prediction of chloride attack in concrete using a numerical model can provide some effective strategies in designing the durability of new RC structures, and forecasting and prolonging the service life of existing RCSs. In the previous investigations, the empirical linear, Langmuir, or Freundlich binding isotherms have been generally used to express the relationship between free and bound chlorides in the numerical transport models of chloride transport in concrete. Essentially, the chloride binding is the result of the physical and chemical reactions between pore solution and hydration products. Herein, the reactive transport model has been established to investigate the chloride attack in concrete, in which the thermodynamic modeling has been developed to describe the chloride binding behaviors in concrete.



Considering that electrochemical protection technologies, i.e., cathodic protection (CP), electrochemical chlorine removal (ECR), electrochemical realkalization (ERA), are considered to be the most direct and effective ways to control the corrosion of RC structures, the active electric field corrosion control method for RC structures that integrates CP, ECR and ERA is proposed. The ionic migration in concrete determines the efficiency of its corrosion control for RC structures, and hence, the reactive transport numerical have been applied to the active electric field corrosion control. In this model, the ionic transport, thermodynamic equilibrium and electrode reactions are included. Additionally, the effects of cracking of concrete and variation of saturation degree on the corrosion control have been investigated.