TG-DTG/DSC, XRD, SEM VE FTIR ANALİZLERİ KULLANILARAK YÜKSEK SICAKLIK KOŞULLARINA MARUZ KALAN ÇİMENTO HAMURUNUN BOZULMASININ KARAKTERİZASYONU

Öz

CEM I çimento hamurunun yüksek sıcaklık davranışı, 25 ila 1000°C arasında hava atmosferinde meydana gelen yapısal ve kimyasal değişiklikleri değerlendirmek için TG–DTG/DSC, BET, XRD, SEM ve FTIR analizleri kullanılarak incelenmiştir. TG–DTG/DSC deneylerinden elde edilen bozunma profilleri üç farklı bölge ortaya koymuştur: (i) C–S–H jelinin ve gözenek suyunun dehidratasyonu, (ii) portlanditin dehidroksilasyonu ve (iii) kalsitin dekarbonasyonu. Her bozunma adımı için karakteristik sıcaklıklar belirlenmiş ve kinetik parametreler Ortega yöntemi kullanılarak hesaplanmıştır. BET analizi, mikro gözenekli yapının kapsamlı bir şekilde çatladığını gösterirken, XRD, SEM ve FTIR, yüksek sıcaklıklara maruz kalan çimento hamurlarındaki faz dönüşümleri ve mikro yapısal evrim hakkında bilgi sağlamıştır. Isıtma hızının (2,5, 10 ve 20°C·dak-1) termal davranış üzerindeki etkisi de değerlendirilmiş ve bozunma süreçleri üzerindeki etkisi vurgulanmıştır. Bu bulgular, çimentolu malzemelerin yangın koşullarındaki termal kararlılığı ve bozunma mekanizmalarının daha iyi anlaşılmasına katkıda bulunmaktadır.

Anahtar Kelimeler

• çimento hamuru
• yüksek sıcaklık
• TG-DTG/DSC
• Yapısal Analiz
• Kinetik Analiz

Destekleyen Kurum

ATATÜRK ÜNİVERSİTESİ BAP KOORDİNATÖRLÜĞÜ

Proje Numarası

FHD-2018-6654

A CHARACTERIZATION OF CEMENT PASTE DEGRADATION EXPOSED TO ELEVATED TEMPERATURES CONDITIONS USING TG-DTG/DSC, XRD, SEM, AND FTIR ANALYSES

Öz

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. BET analysis indicated extensive cracking of the micropore structure, while XRD, SEM, and FTIR provided insights into phase transformations and microstructural evolution in cement pastes exposed to elevated temperatures. The effect of heating rate (2.5, 10, and 20°C·min-1) on thermal behavior was also assessed, highlighting its influence on the degradation processes. These findings contribute to a better understanding of the thermal stability and degradation mechanisms of cementitious materials under fire conditions.

Anahtar Kelimeler

• Cement paste
• high temperature
• TG-DTG/DSC
• structural analysis
• kinetics analysis

Proje Numarası

FHD-2018-6654

Kaynakça

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