Abstract: In order to solve the transmit problem of chloride ion in concrete under the composite effect of flexural tensile load and carbonization in the salt fog area, experiments were designed to study the impact of flexural tensile load and carbonization on the chloride diffusion,respectively.Moreover,since flexural tensile load can influence the carbonization process,which further impacts the chloride ion diffusion,the experiment of load''s impact on the carbonation depth was also designed for the research.With Fick''s Second Law as the benchmark model, a new model of chloride ion diffusion under the composite effect of flexural tensile load and carbonization has been constructed based on the above experiment data as well as existing studies.This model have some positive sense when to predict the flexural member service life in the salt fog area.Experiment outcomes are in line with the results calculated based on the theoretical model with a minor error of under 5%,which further illustrates the validity of step-by-step model construction.

Key words: flexural tensile load;carbonization depth;coupling effect;chloride ion diffusion coefficient;service life prediction