Effect of trass, granulated blast furnace slag and fly ash on delayed ettringite formation

Topbaş, Selim
Properly proportioned, placed and cured concrete can be durable under most conditions. However, deterioration of concrete does occur under certain environments. One of the problems that affect the durability of hardened concrete is delayed ettringite formation (DEF) which is an important problem encountered in precast concrete industry where high temperature curing is applied. Although there had been many researches on DEF, there are still many uncertainties about its chemistry and mechanism. In this study, the effects of partial cement replacement by different mineral admixtures (trass, blast furnace slag and fly ash), SO3/Al2O3 molar ratio and specific surface area of cement on DEF were investigated. For this purpose, 9 groups of control cements were prepared with 3 different specific surface areas and 3 different SO3/Al2O3 molar ratios. Different amounts of mineral admixtures were blended with the control cements. High temperature curing was applied to the cement pastes and the expansions of these pastes were measured periodically for 240 days. v The experimental results obtained were interpreted for a comparative analysis of the effects of the afore-mentioned parameters.


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Calcium aluminate cement is a special cement that reaches high strength in a short time but suffers a considerable loss of strength due to moisture and temperature-related conversion of metastable calcium aluminum hydrates. The study aimed to produce stratlingite as a stable hydration product to completely stop or reduce this chemical conversion using an inexpensive and abundant silica source. Ground perlite was chosen as the source of silica. Perlite was mixed with calcium aluminate cement in different pro...
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Citation Formats
S. Topbaş, “Effect of trass, granulated blast furnace slag and fly ash on delayed ettringite formation,” M.S. - Master of Science, Middle East Technical University, 2010.