Transient meshless boundary element method for prediction of chloride diffusion in concrete with time dependent nonlinear coefficients

► We develop a numerical model for diffusion problem with time dependent nonlinear coefficients. ► Concentration-coupled diffusivity significantly affects chloride diffusion. ► Time dependent nonlinear coefficient model is more accurate than the constant coefficient model. ► The rate of chloride penetration process in concrete is nonlinear with the exposure period.