Comparison of procedures for the evaluation of time dependent concrete diffusion coefficient model

Abstract

The article focuses on approaches for the computation of the input parameters of the time-dependent service-life model for the resistance of High Performance Concrete mixtures (HPC) against chloride ion penetration. The resistance of chloride ion penetration due to corrosion is described by means of diffusion coefficient. The diffusion coefficient is derived from the non-destructive testing method of electrical resistivity based on electrochemistry and following AASTHTO TP-95 specification. The effect of concrete maturity on the diffusion coefficient is taken into account via aging factor. In addition, the application of the least square method is presented and compared with the logarithm-based method in order to approximate the aging factor and reference diffusion coefficient. The quality of approximation of both approaches including the effect of the reference diffusion coefficient selection is also evaluated. Further, the derivation for the computation of model input parameters of both methods is presented. Finally, evaluation of goodness of fit of both approaches is conducted, and recommendation has been proposed via Least Square method and coefficient of determination.