| Summary: | 碩士 === 國立成功大學 === 土木工程學系 === 89 === It needs to spend many years estimating the durability of concrete structures, but constructor couldn't wait for such a long time. Therefore, we hoped to use accelerated methods to speed up destruction to get the long run result of durability in a short-term. In this study, there were two kinds of concrete, NWC(Normal Weight Concrete) and LAC(Light-weight Aggregate Concrete), and three kinds of curing period, 7、14 and 28 days. Experiment was carried out on 10X20cm cylinder.
The accelerated terms were as follows:
１. Solutions were water and saturated sodium sulfate.
２. Temperatures of solutions were 20 and 38.
３. Dry-Wet cyclic times were twenty-one for NWC and fourteen for LAC.
Dry-Wet cyclic method was according to ASTM C88, immersed 16~18 hours and dry 4~6 hours.
In each cycle, we determined the mass and length change, strength change with UST and impacted hammer, micro structure change with SEM, and steel corrosion voltage with M.C.M. Finally, there were three same specimens immersed in saturated sodium sulfate solution to evaluate the reappearance of accelerated method.
The test results are as follows:
１. Dry-Wet cycle had the best accelerated result, but solution and temperature had no effort.
２. The Coefficient Variation of mass changes only between +3 to -7%. It proved a nice reappearance in this accelerated method.
３. Low water/cement could lower probability of steel corrosion, but water/cement and probability of steel corrosion were not direct proportion.
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