Multiscale lattice Boltzmann-finite element modelling of chloride diffusivity in cementitious materials. Part II: Simulation results and validation

• A multiscale method is proposed to estimate chloride diffusivity in concrete.
• The 3D structures of cement paste, ITZ, mortar and concrete are generated.
• The effects of various factors are investigated in a quantitative manner.
• The simulated results show a good agreement with experimental data.
• The estimated chloride diffusivity is used as input for service life prediction.

Chloride diffusivity in cementitious materials depends on the underlying microstructure and environmental conditions. The algorithms and implementation of the multiscale lattice Boltzmann-finite element scheme for prediction of chloride diffusivity in cementitious materials was described in detail in Part I (Zhang et al., 2013). Based on the obtained microstructures and the developed multiscale modelling scheme, chloride diffusivity in cementitious materials at the micro- and meso-scales, i.e. cement paste, mortar and concrete, are estimated and presented in Part II. The influences of w/c ratio, age, chloride binding, degree of water saturation, interfacial transition zone (ITZ) and aggregate content on chloride diffusivity are investigated in a quantitative manner. The simulations are validated with experimental data obtained from literature. The results indicate that the simulated chloride diffusivity in cementitious materials at each scale shows a good agreement with experimental data. In addition, the chloride binding, degree of water saturation, ITZ and aggregate content play significant roles in the chloride diffusivity in cementitious materials. The estimated chloride diffusivity in cementitious materials in this study accounting for the evolution of microstructure and environmental conditions can be directly used as input for the service life prediction of reinforced concrete structures.