Hydration development of mineral additives blended cement using thermogravimetric analysis (TGA): Methodology of calculating the degree of hydration

•The hydration degree of pastes was investigated, using TGA methods.•A modified TG method for calculating the hydration degree was suggested.•The suggested method was validated by hydration heat and compressive strength. Reducing environmental pollution is becoming an important issue that must be taken into consideration, particularly, when producing concrete. Mineral additives used as cement replacement should help in achieving economic performance and ecological pollution reduction. A key question concerning the performance of mineral additives blended cement is the assessment of the contribution of mineral additives to the hydration kinetics. In this paper, the hydration degree of cement pastes containing blast furnace slag and limestone filler was investigated. The investigation was conducted first by using classical thermogravimetric analysis (TGA) methods, which are based on ultimate chemically bound water estimation. A modified TG method based on the direct estimation of the amount of mineral additives contributing to hydration reactions, was then suggested. The accuracy of the suggested method was verified using an isothermal calorimetry test on paste specimens and a compressive strength test on mortar specimens.