engleski

Fly ash as an active mineral addition to Portland cement and concrete

In the few decades, much research has been directed towards the utilization of industrial waste materials (slag, silica fume, limestone dust, fly ash) in cement or in concrete. When these wastes, as mineral additions, are added to cement/concrete, they modify the properties of fresh and/or hardened cement hydration products. In the present work, the physical, chemical, compositional and pozzolanic properties of fly ash, emerging as a by-product of combustion of coal in coal-fired power plants (the Thermal Electricity Station Plomin 2, Croatia), and the quality requirements for fly ash for use as a mineral addition in Portland cement and concrete have been investigated. A number of techniques including XRD, IR spectroscopy, EM and TG/DTG were used to determine the characteristics of fly ash used.Several methods, which are based on the analysis of the pozzolanic reaction in lime-fly ash and cement-fly ash systems, have been applied to evaluating the pozzolanic activity of fly ash. The results showed that fly ash belongs to ASTM Class F type (with a low content of CaO) and exhibits pozzolanic properties. The knowledge of the fly ashs properties will help in providing a better understanding of the factor that control their performance in concrete. Therefore, further research is certainly needed to fully elucidate the effect of fly ash on the mechanical properties of concrete.

industrial waste management; fly ash; Portland cement; concrete

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