시화호 환경 변화에 따른 강재 표면의 부식특성 변화

Variation of Corrosion Properties on the Steel Surface by Environmental Changes in Shihwa Lake

Abstract

Harsh seawater environment is subdivided into marine atmosphere, splash zone, tidal zone, submerged zone and bottom of sea depending on the exposed part. Since corrosion rate depends on the conditions of the exposed parts, proper protection and maintenance for each parts are essential for long-term use of steel structures in seawater environment. For steel structures which were installed in Shiwha Lake, a special maintenance system is required to guarantee its long-term durability and safety. As the tidal power plant has recently been operated, the salinity has risen due to the rapid influx of seawater upstream into Sihwa Lake and the corrosion tendency of the structure is variable according to the water level fluctuation. In this study, corrosion properties of steel structures under water level fluctuation was evaluated by corrosion rate measurement, visual inspection and natural potential measurement and their durability and life management were discussed in view of the effect of variation in of seawater level fluctuations in Shihwa Lake.

Fig. 1. Experimental location for corrosion rate evaluation of steel piles and steel bars

Fig. 3. Corrosion state of steel surface according to the exposed parts

Fig. 4. Comparison to corrosion rate of steel bar by test conditions

Fig. 5. Water level fluctuation of shihwa lake according to the time

Fig. 6. Salinity variation of shihwa lake by the time

Fig. 7. Corrosion rate of steel according to the exposed environment and corrosion mechanism

Fig. 8. Observation of appearance for steel pile according to the time

Fig. 9. Result of natural potential measurement according to the water level

Fig. 2. Observation of appearance for steel bar by the test condition

Table 1. Experimental conditions for corrosion rate evaluation of steel bars and steel piles

Table 2. Chemical composition of steel bars and steel pipes