Abstract The processes of heat penetration into a concrete mass are extremely important. Under high temperature effect, chemical composition and physical structure of concrete changes. These changes are primarily observed at the cement paste and then at the aggregates as well. In this paper, the effect of high temperature on thermal conductivity and moisture resistance factor of concrete with different types of pozzolans and aggregates is investigated. These parameters are analyzed in eight different types of concrete mixes depending on the presence of silica fume, granulated blast furnace slag and fly ash with siliceous and calcareous aggregates. In the scope of this study, simplified formulas of second order with high correlation factors have been derived that give thermal conductivity and moisture resistance factor as a function of temperature in the range of 0–600 °C for the concrete series separately.