“Synthesis, properties of α-C2SH and its application for the production of hydraulic binder material” Doctoral Thesis

Author, institution: Rokas Gendvilas, Kaunas University of Technology

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

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

Scientific Supervisor: Prof. Dr. Raimundas ŠIAUČIŪNAS (Kaunas University of Technology, Technological Sciences, Chemical Engineering – 05T).

Dissertation defence board of Chemical Engineering Science Field:

Prof. Dr. Rimvydas KAMINSKAS (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. Jonas BALTRUŠAITIS (Lehigh University, Technological Sciences, Chemical Engineering – 05T);
Assoc. Prof. Dr. Gintautas SKRIPKIŪNAS (Vilnius Gediminas Technical University, Technological Sciences, Civil Engineering – 02T);
Prof. Dr. Virgilijus VALEIKA (Kaunas University of Technology, Technological Sciences, Chemical Engineering – 05T).

Annotation:

The aim of this work was to create an environment-friendly technology for producing a new hydraulic binder material, based on the hydrothermal synthesis of calcium silicate hydrates and their subsequent tribochemical and low-temperature thermal activation, as well as to examine its hydration process and determine its main properties The influence of the initial materials nature, NaOH additive and parameters of the hydrothermal synthesis on the formation process of the main precursor α-C₂SH, its purity, dispersity and stability was determined. It was proved that bonds, which stabilize the structure of α-C₂SH, are destroyed during the tribochemical and subsequent thermal activation of its mixture with quartz sand and, as a result, hydraulically active amorphous and crystal compounds are formed. It was determined that the same five stages of the hydration, that are characteristic to ordinary Portland cement and belite cements, are also characteristic to the produced silicate binder material. This binder material is suitable for the production of mortars (1:1 by mass with sand), compressive strength of which exceeds 20 MPa after 28 days of hydration. These values match the strength requirements for the belite and special low-heat cements.