Technology of blended Portland-PFA cement with the basic fly ash from TPPs

Blended Portland-PFA cement made of basic coal fly ash from TPPs of Kansk-Achinsk basin has been examined. The main parameters of the composition and production process of such cement were identified, taking into account the deformations of ash-cement matrix after steaming in the autoclave at a pressure of 2.1 MPa. It was established, that the optimum dosage of the high calcium fly ash was 30 %, and the optimum energy consumption for blended Portland-PFA cement grinding was 75—100 % of energy consumption for grinding of Portland cement mix of clinker and gypsum. It was shown that if the use of ash leads to excessive deformations during blended Portland-PFA cement matrix expansion, the most effective way to eliminate those is using active mineral additives (AMA): microsilica fume, granulated blast furnace slag, sour ash from thermal power plants. A methodology for calculating the quantity of AMA for blended Portland-PFA cements containing such kinds of ash has been proposed. The technology can be implemented at cement plants, concrete mixing units, precast concrete factories.

Author: G.I. Ovcharenko, E.Yu. Khizhinkova

Section: Waste utilization

Keywords: ash Portland cement, basic (high-calcium) fly ash, parameters of technology