EXPERIMENTAL STUDY ON STRAY CURRENT CORROSION OFREBAR IN SUBWAY TUNNEL

摘要

Stray current corrosion of rebar in subway tunnel was studied in this paper. Reinforcedrnconcrete specimen was prepared as actual condition. The overpotential of rebar keep at about 0.5V byrncontrol the stray current. The corrosion experiment last one year. The result of weight-loss methodrnshowed that the average corrosion rate of the rebar was 2.388 ×10-3 g·(m 2 ·h) -1, and corrosion depth isrn2.682 ×10-3 mm·a -1 after one year's experiment, keeping overpotential at 0.5V. But relatively seriousrnlocalized corrosion was also found in the experiment.rnOpen-circuit-potential of the rebar shifted in noble direction at the beginning of the experiment and thenrnarrived at a steady level.rnX-ray diffraction analysis for the corrosion product showed that the main component of the corrosionrnproduct was Fe2O3·H2O, some silicon compound was also found and Cl was undiscovered. The energyrndispersion spectroscopy (EDS) analysis of the corrosion product also showed that the main peak were Fernand O, the other lower peak were silicon and calcium, and Cl peak was not found. That was to say that thernmain component of corrosion product derived from the steel and cement and no other unusual componentrnwere found, which was consistent with the result of X-ray diffraction analysis.