Influences of multiple factors on the chloride diffusivity of the interfacial transition zone in concrete composites

Modelling of Chloride Concentration Profiles in Concrete by the Consideration of Concrete Material Factors under Marine Tidal Environment

“…Coarse aggregate is generally one of the main components for concrete composites, and its shape, volume fraction, particle grading, and random distribution within mortar should be comprehensively considered in the mesoscopic numerical model for concrete. In addition, the ITZ is regarded as the loosest zone in concrete, which easily cracks under a series of external loads compared with the mortar phase [37,45].…”

“…The convection zone widths for the experimental mortar and concrete specimens are 6 mm and 4 mm, respectively. This is because the coarse aggregate hardness and compactness exceed those of the mortar [37]. If the coarse aggregate proportion in the convection zone is larger, then the available chloride transport medium in the concrete and the overall porosity within the region will also be reduced accordingly [33,40], and convection will be inhibited.…”

“…The coarse aggregate phase in concrete composites is generally regarded as impermeable; thus, its apparent chloride diffusion coefficient is set as D ca = 0 m 2 /s. For the ITZ phase, the ITZ thickness, i.e., t itz = 0.05 mm, is selected as representative during the numerical simulation process [37]. The ITZ chloride diffusion coefficient is defined as…”

“…Wu et al [36] carried out an indoor real-time tidal cycle experiment, quantified the effect of VFCA on chloride diffusion parameters, and established a two-dimensional chloride diffusion model taking into account the effect of VFCA. Wu et al [37] obtained the chloride diffusivity in concrete with different VFCAs by RCM and further revealed that the chloride diffusivity for concrete decreases with increasing coarse aggregate volume fraction. Du et al [32] employed the finite element method to quantify the influence of VFCA on chloride diffusivity for concrete models, and the results indicated that an increasing VFCA can cause an obvious decrease in the chloride diffusivity of concrete.…”

“…It was concluded that the chloride diffusion concentration increased with decreasing MSCA, and the surface chloride concentration had nothing to do with the coarse aggregate factor. Wu et al [37] indicated that a larger MSCA led to a larger chloride diffusion coefficient in the interface transition zone (ITZ), which represents the chloride diffusion capacity of the ITZ. In addition, an empirical model of the ITZ chloride diffusion coefficient accounting for the MSCA was proposed.…”