| Summary: | 碩士 === 國立臺灣大學 === 土木工程學研究所 === 102 === In the ponding test for concrete durability experiment, chloride ions are allowed to diffuse into concrete, with which concrete durability is assessed. One drawback of the test is that it takes pretty long time. This can be improved by application of electric field that accelerate chloride permeation into concrete. In this study, external pressure was applied to speed up chloride permeation to shorten the test time.
This study applied pressure to accelerate chlorides permeation－ concrete with chlorides seepage got evaluated by a series of layers, each was in 0.5cm of thickness; under pressure, chloride concentration was measured at particular depths to be studied its shifting mechanism and its state of permeation at different trial times and at different W/B. The results were compared with those of the ponding test.
The results came out as followed: the number of chlorides from 60 days of ponding test is smaller that of 20 days of pressured permeation, but larger than that of 7 days of the same one. The amount of chlorides from 60 days of ponding test is about equivalent to that from 13 days of pressure permeation. On a standpoint of permeation depth, with the depth of chloride permeation at its concentration of 0.005% as an indicator, the depth measured from ponding test of 60 days is deeper than that of 20 days of pressured permeation, and is about equivalent to that from 25 days of pressured permeation. The analysis performed with the formula presents the process of 20-day chloride permeation. It is concluded that 70% of total chlorides are brought about by permeation and 30% by diffusion.
|
|---|
