Research results

Since 2003, the following achievements have been made and published:

• Mastering of the preparation technology of pastes, mortars and concretes from brown coal fly ashes on:
  • laboratory test pieces with dimensions up to 0.5 m;
  • exterior interlocking pavers;
  • test beams 3 m in length;
  • contact with Portland cement.

• Finding the optimum composition of activators for reaching maximum strengths.
• Production of leaches of activated fly ashes.
• Fixation of heavy metals in the geopolymer matrix.
• Chemical resistance in strongly acid and alkali media.
• Study of the bond of concrete reinforcement in the geopolymer matrix.
• Preparation of geopolymer concrete at laboratory temperatures without a necessity of tempering.
• Clarification of basic mechanisms of alkaline activation and their relation to macroscopic properties.
• Specification of micromechanical properties on a level below ~800 nm using nanoindentation.
• Homogenization methods predicting a growth in the modulus of elasticity during maturing.
• Clarification of some mechanisms of alkaline activation.

During research, a necessity for further investigation and explanation of the following problems arose:

• The excess of alkalis in the system and their potential transport causing efflorescence.
• Gel syneresis and correlations with macroscopic properties.
• Gel structure and coexistence with potential C-S-H gel.
• Further specifications of an alkaline activation volume model.
• Technological application of plasticizers and air-entraining agents.