| dc.description.abstract | The barriers of facilities which dispose wastes with low radioactivity are mainly composed of concrete, but unlike the normal purpose of concrete, it should be used for more than several hundred years. However, due to Taiwan’s geographic feature- island, the sites of such facilities are mostly placed in marine environment, which will cause immense influences on the degradation and durability of concrete over a long period of time.
This research aims on studying the degradation level of concrete while percolated by chloride ions, through using diffusion coefficient and threshold chloride concentration in empirical formulas, along with doing relative tests and analyses with HIC, ACI, to predict the time when reinforcing steel starts to be corroded. According to the test result, the internal structure of concrete which has low W/B or is blended with pozzolanic materials is comparatively denser, leading to the low diffusion coefficient of chloride ions. But chloride ions may constantly accumulate on the surface of concrete, setting up a high concentration chloride profile.
By using diffusion coefficient to determine the ability of concrete to resist chloride penetration, research consequence reveals that HIC-C and HIC-M result is preeminent compared with ACI in an obvious way. On the other hand, owing to the fact that concrete’s changes with W/B, the resistant ability of concrete changes too. Random. number and empirical formulas are used to predict the time to corrosion initiation while chloride ions percolate and start to destroy the reinforcing steel’s barrier function.
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