Lattice Mesoscale modelling of Chloride Penetration in Concrete: Effect of aggregate volume fraction and fly ash

Abstract

Chloride ions penetrated into reinforced concrete members causes rebar corrosion and induce the volume expansion of the rebar and cracks of concrete cover. This study aims to predict the chloride ingress in the reinforced concrete member and its operational service life by using a lattice model. Concrete is considered at the mesoscale, which constitutes three phases: aggregates, cement matrix and interfacial transition zones (ITZ). Fick’s second law was implemented into the lattice model to describe the diffusion of the chloride ions within concrete. The diffusivity coefficient of aggregates is almost null, whereas those of cement paste and of ITZ is deduced from macroscopic diffusivity measures. Numerical solutions are validated against the test data and the analytical solution. The effect of the aggregate volume fraction is discussed. Curves, which help to determine the service life of the reinforced concrete structure from the cover thickness, is resulted from the lattice modelling for concrete with different aggregate volume fractions.

Keywords

• chloride diffusion
• concrete
• mesoscale
• lattice model
• service life
• cover thickness