Open AccessIn situ powder diffraction study of belite sulfoaluminate clinkering
Author(s) -
De la Torre Ángeles G.,
Cuberos Antonio J. M.,
ÁlvarezPinazo Gema,
Cuesta Ana,
Aranda Miguel A. G.
Publication year - 2011
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049511005796
Subject(s) - belite , materials science , aluminate , powder diffraction , silicate , hematite , phase (matter) , thermal decomposition , synchrotron , chemical engineering , mineralogy , clinker (cement) , portland cement , metallurgy , cement , chemistry , crystallography , organic chemistry , physics , nuclear physics , engineering
Belite sulfoaluminate (BSA) cements have been proposed as environmentally friendly building materials, as their production may release up to 35% less CO 2 into the atmosphere when compared with ordinary Portland cement fabrication. However, their formation mechanism has not been studied in detail so far. Here, an in situ high‐temperature high‐resolution synchrotron X‐ray powder diffraction study is reported. Two types of BSA clinkers have been characterized, both containing 50–60 wt% C 2 S and 20–30 wt% C 4 A 3 as main phases. One type is iron‐rich and a second type (with different phase assemblage) is aluminium‐rich. Furthermore, the C 2 S phase reacts slowly with water, thus activation of this compound is desirable in order to enhance the mechanical strength development of the resulting cements. To do so, iron‐rich BSA clinkers have been doped with minor amounts of B 2 O 3 and Na 2 O to promote stabilization of α‐forms of C 2 S, which are more reactive with water. The decarbonated raw materials were loaded into Pt tubes and heated to between 973 K and 1673 K, and patterns were collected using a high‐energy synchrotron beam of wavelength λ = 0.30 Å. The thermal stability of Klein's salt in these clinkers has been clarified. Several reactions have been followed: formation and decomposition of Klein's salt, melting of aluminates and ferrite, and polymorphic transformations of dicalcium silicate: ‐C 2 S →α‐C 2 S. Changes in mineralogical phase assemblages at a given temperature owing to the addition of minor amounts of selected elements have also been determined.