Title: A New Accelerated Rapid Chloride Permeability Test for Measuring Permeability of HPC for Highway and Bridge Applications
Author(s): R.K. Panchalan and V. Ramakrishnan
Publication: Symposium Paper
Appears on pages(s): 133-148
Keywords: accelerated curing; high performance concrete (HPC); rapid chloride permeability
This paper presents the results of an experimental study to develop a new accelerated Rapid Chloride Permeability Test (RCPT). This research was conducted as part of a project for the South Dakota Department of Transportation (SDDOT). The present ASTM C1202 test method "Electrical Indication of Concrete’s Ability to resist Chloride Ion Penetration" recommends that concrete specimens shall be cured for 56 days prior to testing them for chloride permeability. This curing period would have to be further extended to 90 days for high performance concretes made with fly ash and silica fume. Curing concrete specimens for 90 days would allow the internal microstructure of concrete to fully develop due to conclusion of the hydration process. Therefore it is essential to wait for 90 days to determine accurately the chloride permeability of concrete, unless there is another method, which can be used to accelerate the curing process. This study aims to use an accelerated curing process to determine the chloride permeability values within a shorter duration. Two identical batches of concrete specimens were made with various quantities of silica fume and fly ash. One batch was subjected to standard curing for 90 days and the other was subjected to accelerated curing for 7 days prior to testing them for Rapid Chloride permeability using ASTM C 1202 test method. A mathematical equation was developed to establish a relationship between permeability values of standard and accelerated cured specimens. Statistical analysis was done to validate the obtained relationship. This relationship can be used to predict the 90-day chloride permeability values within a time frame of 7 days.