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The Early Age Hydration Reactions of a Hybrid Cement Containing a Very High Content of Coal Bottom Ash
Author(s) -
Donatello Shane,
Maltseva Olga,
FernandezJimenez Ana,
Palomo Angel
Publication year - 2014
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.12751
Subject(s) - portlandite , ettringite , cement , gypsum , portland cement , clinker (cement) , chemical engineering , mineralogy , hydration reaction , coal , chemistry , materials science , pozzolanic reaction , pozzolan , metallurgy , organic chemistry , engineering
A study examining the complex hydration chemistry of a hybrid alkaline cement containing a high content of coal bottom ash (BA) (>70%) and a low content of portland cement clinker in the presence of an alkaline activator is presented. The use of a water reducing additive was found to significantly delay the overall hydration process, allowing an opportunity to more clearly distinguish the hydration reactions that take place. The results presented showed that both the cement clinker phases and the ash glassy phases are highly reactive for the first 3 d of hydration. In situ formed reaction products portlandite and gypsum were shown to be metastable and had disappeared within 3 d of hydration. Ettringite stability was limited in the hybrid system but unlike gypsum and portlandite, remained detectable for the first 3 d of hydration at least. SEM ‐ EDX and subtracted Fourier transform infrared evidence suggest the development of three different gel bond environments, tentatively attributed to C–(A)–S–H, C–A–S–H, and (N,C)–A–S–H type gels.