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Hydration of C 3 S in presence of CA : Mineral‐pore solution interaction
Author(s) -
Nehring Jörg,
Jansen Daniel,
Neubauer Jürgen,
GoetzNeunhoeffer Friedlinde
Publication year - 2019
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.16197
Subject(s) - dissolution , chemistry , silicate , precipitation , calorimetry , differential scanning calorimetry , calcium silicate , mineralogy , hydration reaction , chemical engineering , inorganic chemistry , materials science , organic chemistry , thermodynamics , cement , metallurgy , engineering , physics , meteorology
C 3 S and CA are the main phases of OPC and Fe‐rich CAC , respectively. The objective of this research was to investigate the influence of CA on C 3 S hydration, representing an under sulfated OPC ‐rich binder, and to shed light on the underlying hydration mechanisms. To this end, C 3 S was blended with 1‐30 wt‐% CA and the pastes (w/c 0.5) were investigated by heat flow calorimetry, in situ X‐ray diffraction and analysis of the pore solution chemistry. CA additions ≥5 wt‐% reveal a separation into three distinct heat flow maxima, whereas additions ≤3 wt‐% just retard the start of the main reaction. The silicate reaction (dissolution of C 3 S and precipitation of C–S–H with or without CH ) can be retarded for 4 to ≥22 hours in comparison to pure C 3 S depending on the admixed CA content. The start of the silicate reaction seems to be related to a decrease in Al‐ and increase in Ca‐concentration in the pore solution. However, it can be shown in this study that C 3 S is able to dissolve even at high Al concentrations in the pore solution.