Influence of Starch Admixtures and Silver Colloids Stabilised with Starch Hydrolysates on the Course of Electrochemical Potential Difference of Reinforcing Steel in High-chloride Environment

The purpose of the conducted study was to verify whether the use of concrete admixtures with modified starches and starches modified with stabilised silver colloids affects the course of electrochemical potential difference, and hence corrosion, of reinforcing steel in a chloride environment. In the tests, cross-linked starches and products of acid hydrolysis of starch (dextrins) were used as admixtures. The 1-molar aqueous solution of sodium chloride was used as an aggressive environment. The tests consisted of measuring the potential difference generated in the reinforcement corrosion cell on the surface for a period of 60 days and then assessing the risk of corrosion. The effect of the addition of starch derivatives on the properties of cement paste was investigated through a one-way ANOVA analysis of variance followed by post hoc tests. The test results showed that the use of concrete admixtures with cross-linked starches positively affects the passivation of the steel. The likelihood of reinforcing steel corrosion when using distarch phosphate, acetylated distarch phosphate and acetylated distarch adipate admixtures is less than 5%. The results obtained showed an improved effect on the passivation of reinforcing steel in cement composites. Additionally, concrete samples may have microbicidal properties.