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Quantitative Phase Analysis of Laboratory‐Active Belite Clinkers by Synchrotron Powder Diffraction
Author(s) -
Morsli Khadija,
De La Torre Ángeles G.,
Stöber Stephan,
Cuberos Antonio J. M.,
Zahir Mohammed,
Aranda Miguel A. G.
Publication year - 2007
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/j.1551-2916.2007.01870.x
Subject(s) - belite , clinker (cement) , rietveld refinement , materials science , phase (matter) , powder diffraction , synchrotron , mineralogy , nuclear chemistry , portland cement , chemistry , crystallography , crystal structure , metallurgy , cement , organic chemistry , physics , nuclear physics
Several active belite laboratory clinkers with a theoretical composition of 60 wt% of C 2 S have been synthesized. The activation process has been carried out by adding variable amounts of alkaline salts, K 2 CO 3 , or Na 2 CO 3 to the raw materials. In addition to an ordinary Portland clinker and a nonactive belite clinker, four active belite clinkers have been prepared with 1.0 and 2.0 wt% of K 2 O or 0.5 and 1.5 wt% of Na 2 O. Phase‐enriched residues, silicate, and aluminate fractions have also been prepared in order to identify the most suitable structural description for each phase. High‐resolution synchrotron X‐ray powder diffraction patterns have been collected for the residues and for the laboratory clinkers. Quantitative phase analyses were performed by the Rietveld method using the synchrotron patterns. The reference belite laboratory clinker has a large amount of β‐C 2 S but the addition of alkaline salts to raw mixtures promotes the stabilization at room temperature of the highest temperature polymorphs: α′ H ‐C 2 S and α‐C 2 S. As an example, the active belite clinker with 2.0 wt% nominal content of K 2 O contains 4.5(2) wt% of β‐C 2 S, 19.2(1) wt% of α′ H ‐C 2 S, 35.9(2) wt% of α‐C 2 S, 17.6(1) wt% of C 3 S, 13.2(1) wt% of total C 3 A, and 9.6(1) wt% of C 4 AF. The role of K 2 O and Na 2 O, which stabilize different polymorphs, will be discussed. The partial volatilization of the alkaline metals will also be addressed. Finally, a calorimetric study has been undertaken in order to correlate the phase assemblage determined in the powder diffraction study with the hydration behavior.