SIMULATION OF CHLORIDE PENETRATION IN CEMENT-BASED MATERIALS

Corrosion of reinforcement in concrete can initiate when chloride ion concentration in contact with steel bars exceeds a threshold value. It is then of crucial importance to describe Cl- penetration through mod els based on fundamental physico-chemical relationships avoiding the u se of empirical parameters. Here, the multicomponent diffusional proce ss was simulated by means of the percolation concepts. Furthermore, th e adsorption of chloride within hardened cement paste was also conside red. General relationships were derived to calculate binding coefficie nts and effective diffusivity of ions as a function of technological c oncrete parameters. The model explains experimental trends in a wide r ange of operating conditions (e.g., with and without superimposed curr ent) both for cement paste and concrete. (C) 1997 Elsevier Science Ltd .