T. Dambrauskas “Synthesis and functional properties of α-C2SH, kilchoanite and hydroxyledgrewite” doctoral thesis defence

Author, Institution: Tadas Dambrauskas, Kaunas University of Technology

Science area, field of science: Technological Sciences, Chemical Engineering, T005

Scientific Supervisor: Prof. Dr. Kęstutis Baltakys (Kaunas University of Technology, Technological
Sciences, Chemical Engineering, T005).

Dissertation Defence Board of Chemical Engineering Science Field:
Prof. Dr. Rimvydas Kaminskas (Kaunas University of Technology, Technological Sciences, Chemical Engineering, T005) – chairman;
Assoc. Prof. Dr. Andrei Rotaru (Craeva University, Romania, Natural Sciences – N003);
Assoc. Prof. Dr. Ramūnas Skaudžius (Vilnius University, Natural Sciences – N003);
Assoc. Prof. Dr. Zenonas Valančius Kaunas University of Technology, Technological Sciences, Chemical Engineering, T005);
Prof. Dr. Virgilijus Valeika Kaunas University of Technology, Technological Sciences, Chemical Engineering, T005).

The doctoral dissertation is available at the library of Kaunas University of Technology (K. Donelaičio St. 20, Kaunas).

Annotation:

The aim of this work is to create an innovative preparation technique for the production of an environmentally friendly cementitious material which will combine the hydrothermal synthesis of calcium silicates and/or calcium silicates hydrates and their solid-state sintering at a low temperature. In this work a new methodology for the formation of anhydrous calcium silicate – kilchoanite – under hydrothermal conditions was developed. In addition, for the first time, a dibasic calcium silicate hydrate, hydroxyledgrewite (Ca₉(SiO₄)₄(OH)₂), was synthesized under hydrothermal conditions (CaO/SiO₂=2.25; 48 h; 200 °C), its physical and chemical properties were investigated, and this compound was used for the production of an environmentally friendly cementitious material. It was estimated that synthetic calcium silicates and/or calcium silicates hydrates formed in non-stoichiometric mixtures; after mechanochemical and thermal activation, they can be used for the manufacturing of environmentally friendly cementitious materials. The properties of the created materials correspond to the requirements of belite and special low-heat cements. The obtained environmentally friendly cementitious materials can be used as an alternative for the ordinary Portland cement. The preparation technique of the above mentioned materials requires a 600–1000 °C lower calcination temperature as well as a lower quantity of calcium carbonate, which leads to lower CO₂ emissions.