This Standard sets out the procedure for determining the immersed absorption (Ai) and, if required, boiled absorption (Ab) and apparent volume of permeable voids (AVPV) in hardened concrete. The drying operation in this test may withdraw the free water that is mechanically held in concrete, and some of the water from the colloidal cementitious gel. The absorptions indicated by the test are larger than those associated with the normal temperature and humidity environment of concrete in service. This method is not intended for use as an absolute measure of durability.NOTES:1 Test results obtained by this procedure will be affected by a number of factors including compaction, curing, absorption, age, air entrainment, absorption and vesicular nature of the aggregate and whether the specimen is moulded, is cut from an existing structure or is a piece of irregularly shaped concrete. Test results may also be affected if concrete specimens are carbonated.2 This Standard may involve the use of hazardous materials and equipment, and engagement in hazardous operations. This Standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this Standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use.