This Standard describes the reference method used for type testing and in cases of dispute for assessing how an aggregate behaves when subjected to the cyclic action of immersion in magnesium sulfate, followed by oven drying. For other purposes, in particular factory production control, other methods may be used provided that an appropriate working relationship with the reference method has been established. NOTE – The majority of aggregates can be tested for performance using this method. Precision has been established for the rock types listed in Annex A. The test may not be suitable for all rock types and reservations have been expressed elsewhere in respect of some carbonate aggregates and some aggregates having a high proportion of magnesium bearing materials or of cryptocrystalline quartz.