Concrete is a durable material in normal circumstance. Also easily degraded by external environment, and hence its service period is shortened. This research is to study concrete in water-to-binder ratio of 0.4, That is also mixed with different materials such as slag and steel fiber. After 28-day curing, 70 days of soaking in artificial brine and repeated loading that stimulates degrading environment, a succession of macroscopic and microcosmic chemical analysis can be processed and electricity can be measured. The result shows that by adding slag can trigger pozzolan effect that greatly improves concrete quality. This can also prevent harmful matter to permeate into RC and to corrode steel. The addition of steel fiber can improve the toughness of concrete as expected, but it also may scarify itself to protect the embedded steel reinforced bar. However, it may reduce the workability of concrete.