Akademik Veri Yönetim Sistemi
Isi Bilimi Ve Teknigi Dergisi/ Journal of Thermal Science and Technology, cilt.46, sa.1, ss.130-140, 2026 (SCI-Expanded, Scopus)
The high-temperature behavior of CEM I cement paste was investigated using TG–DTG/DSC, BET, XRD, SEM, and FTIR analyses to evaluate the structural and chemical modifications occurring between 25 and 1000°C under air atmosphere. The degradation profiles from TG–DTG/DSC experiments revealed three distinct regions: (i) dehydration of the C–S–H gel and pore water, (ii) dehydroxylation of portlandite, and (iii) decarbonation of calcite. Characteristic temperatures for each degradation step were determined, and kinetic parameters were calculated using the Ortega method. Accordingly, the activation energy of Region 1 was determined to be 42.92 kJ/mol. For Region 2, the activation energy was calculated as 151.82 kJ/mol, while in Region 3 it was found to be 152.11 kJ/mol. BET analysis indicated extensive cracking of the micropore structure, while XRD, SEM, FTIR analysis provided insights into phase transformations and microstructural evolution in pastes exposed to elevated temperatures. Also, the effect of heating rate on the thermal degradation of the cement paste was investigated by using DSC data. It was observed that as the heating rate increased, the degradations shifted towards higher temperatures. These findings contribute to a better understanding of the thermal stability and degradation mechanisms of cementitious materials under fire conditions.