Cements Incorporating Brown Coal Fly-Ash from the Latrobe Valley Region of Victoria, Australia

The State Electricity Commission of Victoria generates about 85% of its electrical capacity from the combustion of brown coal mined from extensive coal reserves in the Latrobe Valley region, producing approximately 460 000 tonnes of solid waste annually. This is expected to rise to 550 000 tonnes per year by 1994. Approximately 80% (wt) of solid waste if fly ash.

Black coal fly ashes have been extensively used as extenders for Portland cement, but brown coal ashes are traditionally less satisfactory in cement systems because of their lower hydaulicity and inferior contribution of the ash to the strength development of the matrix. The composition of Latrobe Valley coal and the distribution of ash-forming constituents in the coal result in the formation of a unique fly ash during combustion. The unusual composition and properties of the ash initiated the present study on the potential for using this material in cements and concretes.

The work reported in this paper describes physical and chemical characteristics of Latrobe Valley fly ashes and discusses the formulation of cement blends containing various amounts of fly ash and their properties. Preliminary results show moderate strength development in the products.