Corrosion Prediction of Coated Steel in Magnesium Cement Concrete Based on Wiener Degradation

The corrosion of magnesium cement concrete on steel bars limits its widespread application. To solve this problem, coating is proposed to alleviate the corrosion of steel bars and ensure that magnesium cement-reinforced concrete buildings meet the design requirements over their service life. Based on the natural environment of the Western saline soil area, a rapid corrosion test of magnesium oxychloride-coated reinforced concrete was performed using the solution immersion accelerated corrosion test method. Electrochemical tests of magnesium oxychloride-coated reinforced concrete were periodically conducted using an electrochemical workstation. The electrochemical parameter of corrosion current density, which characterises the corrosion of a coated steel bar, was used as the degradation index; then, a reliability model was built on the basis of the Wiener degradation process, and the corrosion of a coated steel bar was predicted. The results show that the corrosion reliability function of a steel bar coated with magnesium cement-reinforced concrete can be obtained by using the corrosion current density as a durability degradation index, and the coated steel bar reaches moderate corrosion at approximately 30 000 d.