Chloride transport models for wick action in concrete at large Peclet number

Abstract

Wick action is the transport of water and any species it may contain through a concrete element from a face in contact with water to a drying face. Analytical models are presented for chloride transport in concrete due to wick action. Two cases are considered for convection-controlled systems: (1) No precipitation of chloride salt at a wet-dry interface, and (2) precipitation of chloride salt at the interface. For both cases, a constant concentration of chloride salt is assumed for the face of the concrete in contact with salt solution, while at the interface continuity of fluxes is assumed for Case 1, and a constant chloride saturation level for Case 2. Perturbation techniques are used to solve the transient problems for the two cases investigated. The perturbation solution is compared with experimental and numerical results and good agreement is found when chloride binding is accounted for.