ELECTROCHEMICAL EVALUATION OF CORROSION PROTECTION OF REINFORCING STEEL BARS USING SUGARS

This study reports the effect of adding sugars to prevent corrosion of reinforcing bars. The reducing sugars aldose (sugar with an aldehyde group) and, ketose (sugar with a ketone group), and a nonreducing sugar and syrup with an expiration date were used in the experiments. Fehling's reaction, Benedict's reaction, and cyclic voltammetry (CV) tests were performed to investigate the effects of the various sugars on the reductive ability. Because the electrochemical oxidation of sugars requires electrocatalysts, electrodes containing particulate CuO catalysts were used in the experiments. The CV measurements were performed under alkaline conditions to simulate a reinforcing bar in the concrete. The experimental results revealed the influence of different types of sugars on the reductive ability. In Fehling's reaction, fructose was observed to be highly reductive, and its reaction rate was high. In Benedict's reaction, results obtained for waste syrup (WS) were similar to those of fructose, thereby confirming that WS can be used as a reducing sugar. The oxidation onset potentials in the electrochemical experiments were lower for fructose, WS, and glucose, in that order, which was the same as the order of the reaction rates in Benedict's reaction.