The presence of corrosion inhibitors in the composition of building materials is an innovative feature that significantly contributes to the prolongation of the life cycle of reinforced concrete and the rehabilitation procedure itself. Limited control and the high cost of modifying additives result in failure of prescribed dosage and thus limited function. The article describes the methodology for determining the presence of corrosion inhibitors based on amines through a colored reaction of amines with ninhydrin agent.

This paper deals with the evaluation of a partial replacement of cement by Czech fly ash in high strength floor screed in dosage of 10, 20, 30 and 40% and the assessment of the physical-mechanical properties such as compressive strength, water absorption and bulk density. Used fly ashes are from power plants Počerady, Opatovice and Tušimice. The experimental study showed that the use of Czech fly ash improves the compressive strength. The bulk density decreases and therefore water absorption increases. Reference samples become clearly the lowest compressive strength at age of 28 days (fc28). A significant increase in compressive strength (fc28) was observed in case of mix design with addition of 10% and 20% of fly ash Tušimice (10%ETU, 20%ETU) and 20% and 30% of fly ash Počerady (20%EPC, 30%EPC). The addition of 20% of fly ash Počerady (20%EPC) has noticeable influence on short-term compressive strength (measured at the age of 24 hours).

The research presented in this article is focused on analyzing of high temperature influence on behaviour and microstructure of polymeric-cement matrix based repair materials containing lightweight aggregates on the basis of sintered ash. Also admixtures and polymeric fibres were applied to obtain the required parameters. The study of microstructure and its changes was realized using SEM, XRD and DTA analytical methods. Maximum temperature of exposure environment of the tested mortars was 1000°C, while cooling of specimens was gradual.

This paper is focused on clarifying behaviour of concrete at elevated temperature with employing new test set-up constructed at Institute of Building Construction and Technology, Vienna University of Technology. This unique test set-up allows measuring gas permeability of different building materials such as concrete or ceramic at both high temperature (up to 400°C) and pressure (up to 6 bars). Present paper illustrates a new set up for permeability measurement during the heating and cooling and different testing procedures and evaluation of their influence on results.

Results of an experimental study focused on evaluating the suitability of selected alternative additives and their influence on high temperature resistance of repair mortars based on cement are presented in the article. As an alternative substitute, fly ash and blast furnace slag were selected and added in different dosage up to 10% of cement weight not as a substitution component. Aggregates of amphibolite origin were chosen in regard to the thermal resistance to high temperature.