Effect of particle size on heat of hydration of pozzolan incorporated cements

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2014

Öğrenci: MEHMET KEMAL ARDOĞA

Eş Danışman: MUSTAFA TOKYAY, SİNAN TURHAN ERDOĞAN

Özet:

Hydration reactions, the chemical reactions between cement and water are exothermic. The determination of the heat of hydration and rate of heat evolution of cement are extremely important to understand the hydration mechanism. In this study, clinker and gypsum rock were ground after adding natural pozzolan (trass) with various proportions until a specific fineness value and different cements were obtained. These cements were divided into particle size groups with a sonic sifter and the heat of hydration and rate of heat evolution of each cement group were investigated over a 2-day period. In addition, chemical analyses and particle size distribution analyses were performed with the goal of trying to understand whether there was a connection between cement average particle size, pozzolan content and heat of hydration and the rate of heat evolution periods, or not. It is found that, the addition of a small amount natural pozzolan enhances 2-day heat of hydration of cement due to its nucleation effect. However, in the case where higher amounts of pozzolan are used, the hydration heat decreases because of the dilution effect. Moreover, other possible reasons for the changes in rates of heat evolution of different cement groups are predicted to be the alteration in Ca2+ concentration and dispersion effect. It is shown that fine size groups are more reactive than the coarse size groups during hydration. Using the particle size distributions and chemical analyses of size groups, the behavior of the unsieved cement sample can also be estimated. .