Naslov
Chemical Shrinkage During Hydration Reactions of Calcium Aluminate Cement

Autori
Ukrainczyk, Neven

Izvornik
Austin Journal of Chemical Engineering (2381-8905) 1 (2014), 3; 1011, 7

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Calcium aluminate cement ; Hydration ; Chemical shrinkage ; X-ray diffraction ; Mathematical modeling

Sažetak
Calcium Aluminate Cement (CAC) is special cement used in versatile high performance applications. Hardening of CAC is primarily due to the hydration of mono-calciumaluminate, in idealized pure form CaAl2O4, but other minerals also participate in the hydration process especially at higher temperatures and in long term. During the hydration reactions of cement, absolute volume of hydration products formed is smaller than that of its reactants, cement and water, resulting in chemical shrinkage. Chemical shrinkage is the main driving mechanism leading to desiccation and early age cracking of cement based materials. Its evolution is an overall result of complex kinetics of many simultaneous hydration reactions. Even same minerals can have different reaction schemes due to the transformation process of metastable hydration products to the stable ones, which are promoted by temperature. In this paper the hydration of synthetic CaAl2O4 and commercial iron-rich CAC were investigated at 15 and 55 oC by measurements of chemical shrinkage evolution and quantitative powder X-ray diffraction analysis. Design of an experimental configuration for measuring the chemical shrinkage during CAC hydration is discussed. A model is proposed to predict the evolution of chemical shrinkage during hydration. The model is based on the main chemical reaction schemes of the CAC hydration and showed good agreement with the observed experimental results.

Izvorni jezik
Engleski

Znanstvena područja
Kemija, Građevinarstvo, Kemijsko inženjerstvo

POVEZANOST RADA