| Summary: | 碩士 === 逢甲大學 === 土木工程學系 === 105 === This study investigates the behaviors of concrete cylindrical specimens immersed in acid and salty environments. The concrete specimens with/without steel are immersed in acid and salty environments. The chloride ion diffusion contents are measured. The strengths of concrete specimens and pull-out strength of steel bars are also studied.
The reinforced concrete cylindrical specimens are, first of all, made by casting concrete in the cylinder of dimensions 7.5cm × 15cm, 10cm × 20cm and 12cm × 24cm. They are immersed respectively in solutions of 3%, 5%, 6%, 10% different concentrations of sodium chloride (NaCl) and a solution of 4% sulfuric acid (H_2 〖SO〗_4) for 30 days to 330 days. Then, these specimens are removed and under compression test, pull-out test of steel bars, steel corrosion detection and the final chloride ion concentration detection after a soaking period of design days. The data are compared and analyzed.
The results show that the compressive strength of the specimen is subject to significant changes on account of the soaking concentration and duration. In the chloride ion sampling test, the chloride ion content of the sample increases as the soaking duration increases. In the steel corrosion detection, the corrosion rate of the cylindrical specimen increases based on duration, but only the cylindrical specimen with dimensions of 7.5 cm x 15cm corrosion portion increased enough to affect the pull-out strength of steel bars. In the steel pull-out test, only 7.5cm × 15cm cylindrical specimens whereof the pull-out strength has a strong correlation with the change in duration. The cylindrical specimens with dimensions of 10cm × 20cm and 12cm × 24cm have almost no effect after 330 days of immersion.
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