according to standard (ASTM C1202)
The penetration of chloride ions is a major factor that can significantly reduce the durability of concrete. The Rapid Chloride Permeability Test (RCPT) is a reliable method for assessing the chloride permeability properties of concrete. During this test, a cylindrical sample with a diameter of 100 mm and a thickness of 50 mm is subjected to an electric current for a duration of 6 hours, and the total passing charge in the Columbus unit is measured. This value reflects the sample's resistance to the permeability of chloride ions. It's worth noting that the equipment used for this test can also be utilized for measuring the electrical conductivity of hardened concrete (ASTM C1760).