Waste scrap tyres were thermally decomposed at the temperature of 600 °C and heating rate of 10 °C·min⁻¹. Decomposition was followed by the TG analysis. The resulting pyrolytic carbon black was chemically activated by a KOH solution at 800 °C. Activated and non-activated carbon black were investigated using high pressure thermogravimetry, where adsorption isotherms of N₂, CO₂, and cyclohexane were determined. Isotherms were determined over a wide range of pressure, 0.03–4.5 MPa for N₂ and 0.03–2 MPa for CO₂. In non-activated carbon black, for the same pressure and temperature, a five times greater gas uptake of CO₂ than N₂ was determined. Contrary to non-activated carbon black, activated carbon black showed improved textural properties with a well-developed irregular mesoporous-macroporous structure with a significant amount of micropores. The sorption capacity of pyrolytic carbon black was also increased by activation. The uptake of CO₂ was three times and for cyclohexane ten times higher in activated carbon black than in the non-activated one. Specific surface areas evaluated from linearized forms of Langmuir isotherm and the BET isotherm revealed that for both methods, the values are comparable for non-activated carbon black measured by CO₂ and for activated carbon black measured by cyclohexane. It was found out that the N₂ sorption capacity of carbon black depends only on its specific surface area size, contrary to CO₂ sorption capacity, which is affected by both the size of specific surface area and the nature of carbon black.

The reaction products resulting from the alkali-activation of metakaolin are impacted by the composition of the initial kaolin, and amount of alkali-activated kaolinite and water. The present study focused on analyzing these parameters on the metakaolins calcined at 800 °C from three kaolins, and the metakaolins’ alkali activation for 2, 3 and 28 days. The first objective was to evaluate the mineral chemistry and quantitative mineral phase composition from the bulk chemical analysis using the chemical quantitative mineral analysis (CQMA) procedure and conduct a comparison of the chemistry of the metakaolins after alkali activation for 28 days according to the elements Al, Si, Na and K, using the leaching test in distilled water. The second task was to search for possible relationships between the quantitative number of phases in alkali-activated metakaolins and compressive strength. The main methods used for the characterization of material were X-ray fluorescence, X-ray diffraction, thermal TG/DTA and infrared spectroscopy. Metakaolins alkali activated for 28 days contained crystalline quartz, muscovite, orthoclase, and unreacted metakaolinite contained zeolite A (Z-A), hydrosodalite (HS) and thermonatrite (TN) in the amorphous/weakly crystalline phase. The compressive strengths (CS) from 6.42 ± 0.33 to 9.97 ± 0.50 MPa are related positively to H₂O+ and H₂O bound in HS and TN.