Title:
Evaluation of Rapid Chloride Permeability Test (RCPT) Results for Concrete Containing Mineral Admixtures
Author(s):
T. H. Wee, Arvind K. Suryavanshi, and S. S. Tin
Publication:
Materials Journal
Volume:
97
Issue:
2
Appears on pages(s):
221-232
Keywords:
chlorides; concrete durability; electrical resistance; mineral admixtures.
DOI:
10.14359/827
Date:
3/1/2000
Abstract:
The correlation between the charge-passed data derived from rapid chloride permeability test (RCPT) and the chloride penetration coefficient K derived through a 90-day soaking test for the concrete containing mineral admixture is elucidated. For this purpose, concrete specimens containing varying proportions and fineness of mineral admixtures, such as ground granulated blast-furnace slag (GGBFS) and silica fume (SF), and moist-cured for different periods were subjected to a 90-day soaking test and RCPT. To supplement the results, the electrical resistivity and compressive strengths of concrete mixtures were also evaluated. For the majority of mixtures containing SF and GGBFS, the chloride penetration coefficient K and the charge-passed data were following different trends. This suggests that the charge passed and K are the independent properties of concrete controlled by different factors; the charge passed depends on the microstructure and the pore fluid conductivity (especially OH – ions) of the concrete, while K depends primarily on the microstructure of the concrete. Further, the charge passed through SF and GGBFS concrete was shown decreasing exponentially with increasing electrical resistivity of the mixture. Thus, the charge passed through the concrete mixture containing SF and GGBFS can be used as a measure of the overall conductivity of concrete rather than as a measure of the resistance of concrete to chloride penetration. The charge passed was shown related to the compressive strength of SF and GGBFS concrete; the compressive strength increases linearly with the charge passed decreasing.