Yüksek fırın cürufu diatomit ve kalsine kaolinin portland çimento hidratasyonuna etkileri
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Dosyalar
Tarih
2023
Yazarlar
Dergi Başlığı
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Cilt Başlığı
Yayıncı
Düzce Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Geçmişten bugüne kadar çevre bilincinin artması, çimento sektöründeki CO2 emisyonlarının azaltılması yönündeki çalışmaların yoğunlaşmasına sebep olmuştur. Puzolanlar, çevreye verdiği olumlu etkiler ile çimento ve betonun dayanım ve dayanıklılık özelliklerine katkılarından dolayı her geçen gün daha fazla tercih edilen katkı malzemeleri olarak dikkat çekmektedir. Yapılan çalışmalarda puzolanların, fiziksel özelliklerinin çoğunlukla moleküler yapılarına bağlı olduğu ve atom yapılarına göre camsı, amorf ya da kristal yapıda olup kimyasal bileşimine bağlı olarak da değişiklikler gösterdiği bilinmektedir. Bu amaçla yapılan çalışmada bağlayıcı olarak CEM I 42,5 R tipi Portland çimentosu, mineral katkı olarak da yüksek fırın cürufu, kalsine kaolin ve diatomit tercih edilmiştir. Çalışmanın ilk aşamasında hammaddelerin fiziksel, kimyasal, mineralojik, moleküler ve mikro yapıları incelenmiştir. İkinci aşamada bu malzemeler Portland çimentosuna %10 oranında ikame edilerek biri referans olmak üzere dört tip çimento elde edilmiştir. Bu çimento hamurlarının hidratasyon gelişimleri su ihtiyacı, priz süresi, genleşme deneyleriyle ve 28. hidratasyon günü için X ışını difraksiyonu (XRD), fourier kızılötesi dönüşüm spektroskopisi (FT-IR), termal (DSC/TGA) ve mikro yapı analizleriyle (SEM/EDS) incelenmiştir. Üçüncü aşamada ise çimento hamurlarının eğilme ve basınç dayanımları 2., 7., 28. ve 90. hidratasyon günlerinde belirlenmiştir. Elde edilen bulgulara göre mineral katkı ikameli çimento hamurlarının su ihtiyacı ve priz süresi artarken, genleşme değerleri açısından herhangi bir farklılık görülmemiştir. Çimento hamurları üzerinde 28. günde yapılan XRD, FT-IR, DSC/TGA ve SEM/EDS analizlerinden elde edilen veriler, özellikle ileriki hidratasyon sürecinde oluşan portlandit (CH) miktarının tüm mineral katkı ikameli çimento hamurlarında azaldığını ve ilave C-S-H miktarını artırarak çimento hamurlarında daha kompakt bir mikro yapı sağladığı tespit edilmiştir. Sonuçlar, bu mineral katkılarla ikame edilen çimento harçlarının eğilme ve basınç dayanımı değerlerinin 90. hidratasyon gününde referans çimentoya çok yakın değerlerde elde edildiğini göstermektedir. Ayrıca 28. günde, tüm mineral katkı ikameli çimento harçlarının basınç dayanımı değerlerinin, PÇ 42,5 R tipi çimento için belirtilen en küçük değeri olan 42,5 MPa değerinin üzerinde elde edildiği belirlenmiştir.
Increasing environmental awareness from past to present has to led concentrate of studies to reduce CO2 emissions in the cement industry. Pozzolans attract attention as increasingly have been preferred additive materials due to their positive effects on the environment and their contribution to the strength and durability properties of cement and concrete. In the studies, it is known that the physical properties of pozzolans are mostly dependent on their molecular structures and they are glassy, amorphous or crystalline according to their atomic, structure and vary depending on their chemical composition. For this purpose in the study, CEM I 42.5 R type Portland cement was preferred as binder and blast furnace slag, calcined kaolin and diatomite as mineral additives. In the first stage of the study, raw materials were examined physical, chemical, mineralogical, molecular and micro structures. In the second stage, four types of cement were obtained by substituting 10% to Portland cement these materials, one of which was a reference. The hydration developments of these cement pastes were examined by water requirement, setting time, expansion experiments and for the 28th day of hydration by X-ray diffraction (XRD), fourier transforms infrared spectroscopy (FT-IR), thermal (DSC/TGA) and microstructure analysis (SEM/EDS). In the third stage, the flexural and compressive strengths of cement pastes were determined on the 2nd, 7th, 28th and 90th hydration days. According to the findings, in terms of expansion values was not observed difference while the water requirement and setting time of cement pastes with mineral additives increased. The data obtained from XRD, FT-IR, DSC/TGA and SEM/EDS analyzes performed on cement pastes on day 28 show that especially the amount of portlandite (CH) formed during the advanced hydration process decreases in all mineral-added cement pastes and it was determined that it provides more compact microstructure in cement pastes with increased amount of C-S-H addition. The results show that the flexural and compressive strength values of cement mortars substituted with these mineral additives were obtained at values very close to the reference cement on the 90th day of hydration. In addition, on the 28th day, it was determined that the compressive strength values of all mineral additive-replaced cement mortars were above the minimum value of 42.5 MPa, which is the minimum value specified for PÇ 42.5 R type cement.
Increasing environmental awareness from past to present has to led concentrate of studies to reduce CO2 emissions in the cement industry. Pozzolans attract attention as increasingly have been preferred additive materials due to their positive effects on the environment and their contribution to the strength and durability properties of cement and concrete. In the studies, it is known that the physical properties of pozzolans are mostly dependent on their molecular structures and they are glassy, amorphous or crystalline according to their atomic, structure and vary depending on their chemical composition. For this purpose in the study, CEM I 42.5 R type Portland cement was preferred as binder and blast furnace slag, calcined kaolin and diatomite as mineral additives. In the first stage of the study, raw materials were examined physical, chemical, mineralogical, molecular and micro structures. In the second stage, four types of cement were obtained by substituting 10% to Portland cement these materials, one of which was a reference. The hydration developments of these cement pastes were examined by water requirement, setting time, expansion experiments and for the 28th day of hydration by X-ray diffraction (XRD), fourier transforms infrared spectroscopy (FT-IR), thermal (DSC/TGA) and microstructure analysis (SEM/EDS). In the third stage, the flexural and compressive strengths of cement pastes were determined on the 2nd, 7th, 28th and 90th hydration days. According to the findings, in terms of expansion values was not observed difference while the water requirement and setting time of cement pastes with mineral additives increased. The data obtained from XRD, FT-IR, DSC/TGA and SEM/EDS analyzes performed on cement pastes on day 28 show that especially the amount of portlandite (CH) formed during the advanced hydration process decreases in all mineral-added cement pastes and it was determined that it provides more compact microstructure in cement pastes with increased amount of C-S-H addition. The results show that the flexural and compressive strength values of cement mortars substituted with these mineral additives were obtained at values very close to the reference cement on the 90th day of hydration. In addition, on the 28th day, it was determined that the compressive strength values of all mineral additive-replaced cement mortars were above the minimum value of 42.5 MPa, which is the minimum value specified for PÇ 42.5 R type cement.
Açıklama
Anahtar Kelimeler
İnşaat Mühendisliği, Civil Engineering
