Numerical and Experimental Analysis of Self-Protection in Reinforced Concrete due to Application of Mg–Al–NO2 Layered Double Hydroxides

• Concrete possesses an intrinsic chloride binding capacity. Chloride ions from the environment bind with the hydrated cementitious phases in the form of bound chlorides. The contribution of chemically bound chlorides toward increasing the service life of concrete structures is vital as they help in slowing down the chloride diffusion in the concrete thereby delaying reinforcement depassivation. The authors attempt to increase the chloride binding capacity of concrete by adding a small amount of Mg–Al–NO2 layered double hydroxides (LDHs) with the objective to delay reinforcement corrosion and by this to considerably extend the service life of concrete structures situated in harsh environments. This study presents numerical and experimental analysis of the action of LDH in concrete. Formation factor is used to determine the effective chloride diffusion coefficient. In addition, the chloride binding isotherms together with Poisson–Nernst–Planck equations are used to model the chloride ingress. A comparable chloride binding is observed for concrete with and without Mg–Al–NO2, depicting only a slight chloride uptake by Mg–Al–NO2. Further investigations are conducted to understand this behavior by studying the stability and chloride entrapping capacity Mg–Al–NO2 in concrete. © 2020 The Authors.

Nyckelord

concrete

corrosion

finite element analysis

layered double hydroxides

Aluminum corrosion

Chlorine compounds

Concrete buildings

Concrete construction

Electrochemical corrosion

Nitrogen oxides

Chloride binding capacity

Chloride binding isotherms

Chloride diffusion

Chloride diffusion coefficient

Increasing the service lives

Numerical and experimental analysis

Reinforcement corrosion

Reinforced concrete

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