This paper discusses Rapid Chloride Permeability Test investigations on the penetration of chloride ions into the concrete. Concrete samples of M40 and M50 Grades have been tested. The concrete specimens are made using standard molds of 100mm diameter x 50mm height. After curing the concrete samples are experimented. Specimens were cast and tested for 28 days. One chamber is filled with sodium chloride (NaCl) and another sodium hydroxide solution is filled. The strength of sodium chloride solution is varied from 1000ppm-35000ppm and the strength of sodium hydroxide solution are 0.04N. For all the combinations, RCPT was carried out and the charge passed through the specimens was noted. The Rapid Chloride Permeability Test values are found, the penetration charge through the concrete decreased with an increase in the grade of concrete.