AS 1141.34:2018 PDF

This Standard sets out a method for an approximate determination of the presence of organic materials, other than sugar, present in fine aggregate.

The test relies on the reaction of humus material with a sodium hydroxide solution to produce a dark colour in the liquid the intensity of which is approximately proportionate with the mass content of humus in the fine aggregate. Based on 1917 research, fine aggregate with humus contents that have a resultant solution colour lighter than, or equal to, the Standard colour are expected to have no detrimental effects when used in concrete or mortar products. A darker coloured solution may be the result of humus content and/or reactions from other contaminents and may require further investigation to determine the extent of possible effects to concrete or mortar properties.