3D Multi-Ion Corrosion Model in Hierarchically Structured Cementitious Materials Obtained from Nano-XCT Data

Area of Science:

• Materials Science
• Civil Engineering
• Electrochemistry

Background:

• Steel reinforcement corrosion in concrete is a significant global issue.
• Current models often simplify concrete's heterogeneous microstructure, affecting transport coefficient accuracy.
• Accurate modeling requires understanding ion transport and electric potential within the concrete matrix.

Purpose of the Study:

• To develop a more realistic model for assessing rebar degradation in reinforced concrete.
• To investigate ion movement and electrochemical reactions using a detailed 3D concrete microstructure.
• To improve the evaluation of currents responsible for reinforcement mass loss.

Main Methods:

• Obtained real 3D concrete microstructure using high-resolution X-ray computed tomography (XCT).
• Processed XCT data to create a mesh for finite element method (FEM) computations.
• Implemented a multi-species transport and electric potential equation system within the FEM framework.

Main Results:

• The methodology allows for a realistic description of ion movements and reactions.
• Enables a better evaluation of anodic and cathodic currents driving rebar corrosion.
• Results provide a more accurate prediction of reinforcement mass loss and its location.

Conclusions:

• The integrated XCT-FEM approach offers a superior method for analyzing rebar corrosion in concrete.
• This technique enhances the understanding of degradation mechanisms in heterogeneous materials.
• The findings contribute to more reliable structural health monitoring and durability assessments.