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Oil‐Well Cement and C 3 S Hydration Under High Pressure as Seen by In Situ X‐Ray Diffraction, Temperatures ≤80°C with No Additives
Author(s) -
Jupe Andrew C.,
Wilkinson Angus P.,
Funkhouser Gary P.
Publication year - 2011
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.1551-2916.2010.04284.x
Subject(s) - ettringite , slurry , cement , gypsum , materials science , chemical engineering , kinetics , synchrotron , chemistry , mineralogy , composite material , portland cement , physics , quantum mechanics , nuclear physics , engineering
The hydration kinetics of a white cement and batches of both Class G and H oil‐well cements were examined between 0 and 60 MPa, at ≤80°C, using in situ synchrotron X‐ray diffraction. This gives a continuous measure of the C 3 S (Ca 3 SiO 5 ), CH (Ca(OH) 2 ), C 4 AF (Ca 2 FeAlO 5 ), ettringite, and other phases in the hydrating slurries. Slurries prepared from single‐phase C 3 S; synthetic C 4 AF, and gypsum; and white cement, synthetic C 4 AF and gypsum were also examined. An increasing pressure enhanced the rate of hydration for all slurries. Analysis of the data, using a kinetic model, provided rate constants that were used to obtain activation volumes for C 3 S hydration. For all the cement and C 3 S slurries studied, similar activation volumes were obtained (average Δ V ‡ ∼−35 cm 3 /mol), indicating that the presence of cement phases other than C 3 S has a modest influence on the pressure dependence of C 3 S hydration. An alternative analysis, using the time at which 90% of the initial C 3 S remained, gave similar activation volumes. Pressure accelerated the formation of ettringite from synthetic C 4 AF in the presence of gypsum. However, in slurries containing cement, the pressure dependence of C 3 S hydration plays a major role in determining the pressure dependence of ettringite formation.