This British Standard, a part of the BS 812 series, describes two methods for determining the sulphate content of aggregates.
The first method determines the water-soluble sulphate content of aggregates, which applies to natural and synthetic aggregates to be used as drainage materials or for fill or hard core, e.g. unbound road bases or sub-bases or foundations.
The second method determines the total sulphate content of aggregates, which applies to aggregates used in concrete and cement bound materials.
The second method for the determination of total sulphate by acid extraction is specified as it is impractical to produce a method for the determination of total water-soluble sulphate because of low water solubility of calcium sulphate. For practical purposes for aggregates in concrete, the total sulphate content determined by this method is taken to be the same as the total water-soluble sulphate content.
Two procedures for a semi-quantitative test are described in an appendix to this standard. It is strongly recommended that one of these is used as a preliminary check before resorting to the test described in the main text, which may be needed for compliance with a specification.
