V. Česnauskas “Biomass fly ash additive for Portland cement and slag cement” doctoral thesis defence

Author, Institution: Vytautas Česnaukas, Kaunas University of Technology,

Science area, field of science: Technological Sciences, Chemical Engineering – 05T

Summary of doctoral thesis: Summary

Scientific supervisor: Prof. Dr. Rimvydas Kaminskas (Kaunas University of Technology, Technological Sciences, Chemical Engineering – 05T).

Dissertation Defence Board of the Chemical Engineering Science Field:
Prof. Dr. Raimundas Šiaučiūnas (Kaunas University of Technology, Technological Sciences, Chemical Engineering – 05T) – Chairman;
Dr. Valentin Antonovič (Vilnius Gediminas Technical University, Technological Sciences, Materials Engineering – 08T);
Assoc. Prof. Dr. Anatolijus Eisinas (Kaunas University of Technology, Technological Sciences, Chemical Engineering – 05T);
Prof. Dr. Habil. Gundars Mezinskis (Riga Technical University, Technological Sciences, Materials Engineering – 08T);
Prof. Dr. Virgilijus Valeika (Kaunas University of Technology, Technological Sciences, Chemical Engineering – 05T).

The doctoral dissertation is available on the internet and at the library of Kaunas University of Technology (K. Donelaičio str. 20, Kaunas).

Annotation:

As the requirements of the EU environmental and air pollution reduction rules are tightened, the increasing use of renewable energy sources is in progress and the research for new applying possibilities of industrial waste are being sought. One of these sources is biomass. Biomass ashes are rich in amorphous SiO₂, therefore it can be used as a mineral additive and / or activator / binder in cement production and / or in concrete as an alternative to commonly used binding materials. A lot of attention also is paid to research of granulated blast furnace slag, its effect on the properties of cement stone and evaluation of slag cement hydration characteristics. The use of this waste in slag cement production results in lower energy consumption and CO₂ emissions. Biomass fly ash contains alkaline oxides, therefore its additive in the slag cement could destabilize the glassy state phase in the slag during the cement hydration without additional activation of the slag with other chemical reagents. In this dissertation the effect of tribochemically activated biomass fly ash prepared as micro filler on the hydration of Portland cement minerals, cement stone compressive strength and the resistance to alkali–silica reaction and the sulfate attack are determined. Also provided the impact of activated biomass fly ash on the hydraulic properties of granulated blast furnace slag and slag cement hydration process. Technological recommendations for the application of biomass fly ash additive are proposed and calculation of CO₂ emission is given.