Experimental investigation on the effects of temperature and w/c on corrosion characteristics of rebars in concrete exposed to salt lake environments

The high-salinity environments in salt lakes can significantly affect the durability of reinforced concrete. However, there needs to be more reports on the corrosion characteristics of the rebars under salt lake environments, which play a crucial role in studying the deterioration of concrete structures. This study meticulously investigated how temperature variations and changes in water-cement ratios affect the corrosion of rebars in high-salinity lake water conditions, which not only supplements the existing research gap in salt lake conditions but also offers insights for predicting the service life of concrete structures under such circumstances. Reinforced concrete specimens with water-cement ratios of 0.49, 0.54, and 0.60 were tested in both the atmospheric zone and dry–wet cycling zone at temperatures of 15 °C, 30 °C, 35 °C, and 40 °C. A three-electrode system was utilized to monitor the corrosion potentials of the rebars, while the linear polarization method was employed to determine the polarization resistance. The time to corrosion initiation, threshold chloride concentration, and corrosion current density were determined and discussed. The results indicated that temperature and salinity did not significantly affect the corrosion potentials of rebars. However, corrosion initiation occurred much faster under salt lakes than in marine environments, with initiation times averaging around 100 days. Furthermore, it was found that the corrosion rate tended to increase as the temperature and water-cement ratio increased. Additionally, the rebars in the atmospheric zone exhibited lower threshold chloride concentration than those in the dry–wet cycling zone at temperatures of 30 °C, 35 °C, and 40 °C, and higher temperatures corresponded to more significant differences in threshold chloride concentration between the two zones. Lower water-cement ratios were shown to delay corrosion initiation and increase the threshold chloride concentration, suggesting the effectiveness in mitigating rebar corrosion in high-salinity environments. Graphical Abstract