A multi-phase micromechanical model for unsaturated concrete repaired using the electrochemical deposition method

• A multi-phase micromechanical model is proposed for healed unsaturated concrete.
• An approximate modified function is proposed to extend the use of Mori–Tanaka method.
• Composite effective properties are obtained by our multi-level homogenization scheme.
• The prediction of our model can meet well with the existing experimental data.
• Saturation degree, properties of deposition products are important for healing effect.

Most concrete structures repaired using the electrochemical deposition method (EDM) are not fully saturated in reality. To theoretically illustrate the deposition healing process by micromechanics and quantitatively describe the effective properties of unsaturated concrete during the EDM healing process, a multi-phase multi-level micromechanical framework is proposed based on the microstructure of unsaturated concrete and the EDM’s healing mechanism. In the proposed model, the volume fractions of water and deposition products, the water effect (including further hydration and viscosity in pores) and the shapes of pores in the concrete are comprehensively considered. Moreover, multi-level homogenization procedures are employed to predict the effective properties of unsaturated concrete repaired using the EDM. For the first-level homogenization of this model, a modified function is presented to correct the Mori–Tanaka (M–T) method, which is used to predict the effective properties of equivalent inclusions composed of deposition products and water. To demonstrate the feasibility of the proposed micromechanical model, predictions obtained via the proposed multi-phase micromechanical model are compared with the experimental data, including results from extreme states during the EDM healing process. Finally, the influences of equivalent aspect ratios and deposition product properties on the healing effectiveness of EDM are discussed based on the proposed micromechanical model.