An electrochemical method for accelerated chloride migration test of diffusion coefficient in cement-based materials

摘要

In this study, the electrochemical technique is applied to accelerate chloride ion migration in cement-based material to estimate its permeability. The plain cement concrete and concrete containing different type of mineral admixtures (slag and fly ash) with water/binder (w/b) ratios of 0.35, 0.45, 0.55, and 0.65 were used. For all test series, the chloride concentration in the anode cell as well as the electrical current were simultaneously monitored in the accelerated chloride migration test (ACMT). The steady-state diffusion coefficient for concrete was calculated using the constant flux on the basis of the Nernst-Planck's equation and the non-steady-state diffusion coefficient was calculated from the modified second Fick's law. The charge passed from different conditions were separately defined and derived. The results for all mixtures show that the steady-state diffusion coefficient and charge passed obtained from the accelerated chloride migration test under steady-state condition is linearly correlated.