This is a method for evaluatingThe carbonation resistance of concrete mixes by comparison with a concrete mix with known carbonation resistance. It is not a method forThe determination of carbonation depths in existing concrete structures.The test is carried out under controlled exposure conditions using natural levels of carbon dioxide or under natural conditions protected from direct rainfall. IfThe carbonation depth of the unknown mix is equal or less thanThe known mix, it is be assumed thatThe risk of reinforcement corrosion forThe new mix is equivalent toThe known mix (withThe same cover required forThe known mix).The "reference" concrete may be any concrete with known performance inThe intended place of use (environment).