This Standard describes the reference method used for type testing and in cases of dispute for determining the polished stone value (PSV) of a coarse aggregate used in road surfacings. 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. Annex A describes an optional method for the determination of the aggregate abrasion value (AAV). NOTE The AAV method should be used when particular types of skid resistant aggregates (typically those with a PSV of 60 or greater) which can be susceptible to abrasion under traffic, are required.