This European Standard specifies an accelerated laboratory method for measuring the resistance against carbon dioxide penetration through repair products and systems, as defined in EN 1504-3 1). The method is suitable for assessing the performance of repair grouts, mortars and concretes without a protective coating system applied. The method does not measure the resistance to reduction in pH-value that may occur by absorption of other acidic gases (e.g. SO2, HCl etc.).