Multifunctional Inhibition Based on Layered Double Hydroxides to Comprehensively Control Corrosion of Steel Rebar in Concrete

Abstract

Concrete is the most widely used construction material in the world due to its versatility and relatively low cost. However, the early deterioration of reinforced concrete constructions due to corrosion of the steel reinforcement has become a major problem in the society, not only resulting in a huge economic loss, but also inducing serious safety disasters frequently. In this work, A novel multifunctional inhibitor of MgAl-layered double hydroxides (LDHs) loaded with nitrite anions was synthesized via a calcination-rehydration in ambient atmosphere. It was demonstrated that such LDHs loaded with inhibitor was able to comprehensively control the corrosion of carbon steel in simulated concrete pore solution (SCPS) as well as in mortar. Based on the systematic measurements, a conceptual model was proposed for the first time to further understand the mechanism of multifunctional corrosion protection of MgAl-LDHs-NO2 - in steel reinforced concrete, involving the increase of pH and decrease of free chloride ions in concrete, release of inhibitor ions, and impeding the transport process of the aggressive ions in the concrete. Such unique multifunctional composite is markedly helpful to comprehensively control corrosion of steel in concrete.