Standard Specifications for Concrete Structures 2012, Materials and Construction, by Japan Society of Civil Engineers

Axial-Bending Interaction Diagrams of Reinforced Concrete Columns Exposed to Chloride Attack

“…where C(x,t) is the chloride content (kg/m 3 ) at distance x (m) from the surface at a generic time instant t (s); Cs is the surface chloride concentration (kg/m 3 ) and Da is the apparent diffusion coefficient (m 2 /years). Although equation (10) adequately describes the behaviour of the concentration of chlorides in the RC structures, the assumption of a constant diffusion coefficient restricts the use of this equation. The chloride diffusion coefficient decreases with time due to several issues such as continued hydration and chloride binding.…”

“…Schiessl and Raupach [9] stated that the critical chloride ion concentration could be defined as the chloride content that was necessary to sustain local passive film breakdown at the steel depth before the process of corrosion initiation. JSCE [10] defined the critical value of 1.2 kg/m 3 to initiate reinforcement corrosion. In effect, critical chloride value depends on the roughness of steel surface, concrete properties, and the aggressiveness of the environment.…”