Corrosion Rate Evaluations of Bent Steel Bars Immersed in Sand Soils Used in Concrete Reinforcement

Abstract

To understand the corrosion of bent steel bars exposed to sand soils the physicochemical properties were tested and corrosion rates measurements were made in the laboratory as a function of the type of sand used in the production and reinforcement of concrete, of the exposure time, and of a drastic condition (a saturated sand soil simulating a wet concrete by moisture content). Some assumptions were involved in the investigation of activated concretes containing beach and/or pit sand to correlate the corrosion rate of a steel bar measured in laboratory conditions to that used in the field works. The paper presents four techniques to measure the corrosion rate; thus, a comparison of corrosion rates data via electrochemical and weight loss methods was carried out. The analysis of the obtained results suggested that the corrosion susceptibility was almost doubled for a bent steel bar exposed to the saturated pit sand after 74 days of exposure (the corrosion rate was found to be 0.136, 0.010, 0.025, and 0.026 mm/year by using linear polarization resistance, charge transfer resistance of the Tafel plots, and gravimetric measurements, respectively), in comparison with a not bent steel bar. The deviation of corrosion rates was attributed to a more conductive corrosion products resulting in a more active interface with respect to the experimental variables used in the electrochemical and weight loss measurements. The Tafel and weight loss measurements that were close between them must be useful in determining steel bars susceptibility to corrosion in drastic conditions simulating active concretes, to be applied to systems such as construction industries.