Concrete Durability Test (Rapid Chloride Permeability Test)

The permeability of concrete is playing a significant role in determining the service life of concrete, especially in an aggressive environment. The ingress of chloride will adversely affect the concrete. Chloride will cause reinforcement corrosion. The volume of corrosion is estimated to be 3 times the original volume of reinforcing bars. The increase of volume will exert stress on concrete that will lead to cracking and spalling of concrete. Also, corrosion will reduce the cross-section of steel and the tensile strength of reinforcement bars. The strength and durability of reinforced structure will be adversely affected. 

The rapid chloride permeability is a non-destructive test used to measure the resistance of concrete to chloride ion penetration. The migration of chloride through concrete is a slow process even if the permeability of concrete is high. The researchers found that the applying of current to a concrete specimen will accelerate the migration process of chloride to concrete. Using current to expedite the process of chloride migration will help in producing quick and precise test results. 

A cylindrical concrete specimen is cored from the concrete to be tested. The diameter of the specimen is 100 mm with a thickness of 50 mm. The test is conducted by placing the specimen into the RCPT apparatus for 6 hours. 60 DC volt is maintained between sample ends during the test duration. One end will be immersed with 0.3M sodium hydroxide NaOH while the other end is immersed with 3% of sodium chloride NaCl. Based on the charge passes through the concrete specimen, a qualitative rating is made for the concrete tested.  

Figure 2

Table 1

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