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Effect of Phosphorus Impurity on Tricalcium Silicate T 1 : From Synthesis to Structural Characterization
Author(s) -
De Noirfontaine MarieNoëlle,
TusseauNenez Sandrine,
SignesFrehel Marcel,
Gasecki Gilles,
GirodLabianca Caroline
Publication year - 2009
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.1551-2916.2009.03092.x
Subject(s) - alite , scanning electron microscope , calcium silicate , electron microprobe , materials science , phosphorus , cement , crystallography , portland cement , phase (matter) , triclinic crystal system , impurity , analytical chemistry (journal) , silicate , crystal structure , mineralogy , nuclear chemistry , chemistry , metallurgy , clinker (cement) , composite material , chromatography , organic chemistry
Alite is the major compound of anhydrous Portland cement: it is composed of tricalcium silicate Ca 3 SiO 5 (C 3 S) modified in composition and crystal structure by ionic substitutions. Alite is also the main hydraulic phase of cement and the most important for subsequent strength development. Using raw meals (rich in Ca 3 P 2 O 8 ) as alternative fuels in cement plants raises the question about the effect of phosphorus on C 3 S and its consequences on reactivity with water. This paper deals with a systematic study of C 3 S triclinic T 1 polymorph doped with P 2 O 5 in the range 0–0.9 wt%. All the samples were characterized by X‐ray powder diffraction (XRD), scanning electron microscopy (SEM), and electron‐microprobe analysis. The appearance of a phase rich in phosphorus is shown. It displays a structure derivative of the α′ H –Ca 2 SiO 4 polymorph, noted α′ H –C 2 S(P). As phosphorus content increases, C 3 S is more and more decomposed into free lime and α′ H –C 2 S(P). The α′ H phase was detected from 0.1 wt% P 2 O 5 and located at the interfaces of C 3 S grains. Two identification keys are proposed in order to highlight the α′ H –C 2 S(P) phase: the XRD angular window at 2θ Cu =32.8°–33.2° and a smooth aspect on SEM micrographs.