conditions are known, it is only the Critical Chloride Threshold Level (CCTL) of the SSR designation to withstand the predicted chloride level at depth for the design life of the structure that needs to be defined. During the years, many researchers have measured the CCTL for a number of different steels. However, since a number of methods have been used, most of them using synthetic pore solutions; the existing CCTL data is diverse and lack the correlation between cast-in testing with in solution testing. This paper aims to clarify and compare results from some literature data for pore-solution and cast-in methods. It further reports the CCTLs of the following designations; 304L, 316L, and 2304 and carbon steel.

The fact is, CCTL as a subject is not the easiest subject to understand but unavoidable in designation selection choice. A good start to understanding is the critical review paper written by Sara Randström and Murray Adair and published in a special edition of Acom. This special edition contains real examples of both in solution testing and cast in testing.