The document discusses the durability of standard concrete incorporating supplementary cementing materials (SCMs) using the rapid chloride permeability test. It presents test results that show incorporating SCMs like fly ash, silica fume, and metakaolin as partial replacements for cement in an M40 grade concrete mix can improve durability as measured by lower chloride ion permeability compared to conventional concrete without SCMs. The rapid chloride permeability test was performed on concrete specimens according to ASTM standards after 90 days of curing and the total charge passed through in coulombs was measured and used to determine the chloride permeability rating. Concrete mixes containing SCMs showed lower charge values, and therefore better durability ratings, than normal concrete without SCMs.