Characterization of Australian and New Zealand fly ashes for concrete manufacture

The disposal of fly ash produced by modern thermal power stations is an enormous environmental problem, which can be alleviated to a small degree by using the fly ash as a cement additive in the manufacture of concrete. In order to assist the assessment of the feasibility of such utilization, chemical and physical properties of nine different Australian and New Zealand fly ashes were determined with the purpose of relating them to the pozzolanic properties of the ashes. It was found that, while the ashes produced from bituminous and subbituminous coal were generally (apart from the Tarong ash) acceptable as a pozzolanic source, two of three tested ashes produced from brown coal did not meet the required standards. Some ashes, in particular the Loy Yang ash, were found with some additional treatment to be potential pozzolanic additives.