Physical properties of post-process fly ash from TWTP Krakow

Fly ashes from eco-incinerator according to the Art.7 of the Act of December 14, 2012 on waste are a hazardous waste. The growing amount of this type of waste generates a problem in terms of their management. They are a post-process waste, so their chemical composition is not constant and their quality is not very high. In addition, a high content of heavy metals with different concentrations may adversely affect the properties of these ashes. The physical properties of fly ashes originating from the TWTP in Krakow in the light of the requirements of PN-EN 450-1 are analysed in the article. The aim of the paper is a preliminary assessment, based on the tests carried out on three random ashes, to check if there’s a possibility of utilisation of this type of waste in concretes. The results of physical properties examination showed that they are coarse ashes with a several percent moisture content. They meet the requirements of PN-EN 450-1 in terms of the impact on the initial setting time and soundness. They cause an increase in the mortar's water demand. Their compression activity index after 28 days is 63-70%, and after 90 days 56-67% and do not meet the standard requirements (75% after 28 days and 85% after 90 days)