Evaluation of Greener Corrosion-Inhibiting Admixtures for Steel Reinforcements in Concrete

Abstract

In this study, corrosion of thermo-mechanically treated (TMT) rebars with and without 3.5% NaCl for various concentrations (0.1%, 0.2%, 0.3% and 0.4%) of green corrosion inhibitors, namely glucosamine and stevioside, was systematically studied in simulated concrete pore solution (SCPS). Open-circuit potential measurements revealed that inhibited system showed passive behaviour compared with control system in SCPS. Potentiodynamic polarization studies revealed that inhibitor stevioside offers more than 88% inhibition efficiency at 0.3% concentration in SCPS containing 3.5% NaCl. Similarly, linear polarization resistance and impedance measurements showed higher polarization resistance and charge transfer resistance values, respectively, at 0.3% concentration for inhibited systems when compared with control (without inhibitor).In the second part, the optimized concentration of glucosamine and stevioside showed better performance against corrosion of rebar in the solution study admixed into concrete. The corrosion of TMT rebar embedded in concrete with and without inhibitors is subjected to simulated marine exposure for a period of 180 days and evaluated the corrosion inhibition. Gravimetric weight loss and electrochemical techniques were employed to study the efficacy of inhibitors in SCPS and concrete medium. It is found that the time taken for corrosion-induced cracking in concrete admixed with stevioside inhibitor is approximately 20 times that of control concrete and that stevioside inhibitor is relatively better corrosion inhibitor than other inhibitor reported.

Investigation on microstructural and compressive strength characteristics of a novel bio-admixture comprising Cassava Starch-Xanthan gum with cement mortar for building application

“…Such admixtures give chemists the best opportunity to alter characteristics and increase performance through the targeted exploitation of structure/property correlations [5]. A diverse range of admixtures namely superplasticizer, accelerators/retardants, viscosity modifying agents air-entraining admixtures has been widely studied [6][7][8]. Although chemical admixtures influence the rheological and mechanical behavior of cement-based systems, they pose serious threat to the environmental pollution, which may have a negative impact on human health [9].…”