Aminobenzoate modified MgAl hydrotalcites as a novel smart additive of reinforced concrete for anticorrosion applications

A carbonate form of MgAl hydrotalcite, Mg(2)Al-CO3 and its p-aminobenzoate (pAB) modified derivative, Mg(2)Al-pAB, were synthesized and characterized by means of XRD, FT-IR and TG/DSC. The anticorrosion behavior of Mg(2)Al-pAB was evaluated based on open circuit potential (OCP) of carbon steel in simulated concrete pore solution and on chloride-exchange experiments. The results reported in this paper demonstrate that ion-exchange indeed occurred between chlorides and intercalated pAB anions, thereby reducing the free chloride concentration in simulated concrete pore solution. The simultaneously released pAB anions were found to exhibit the envisioned inhibiting effect and caused corrosion initiation of the steel to shift to higher chloride concentrations than without the modified hydrotalcites.