Early age hydration of calcium sulfoaluminate (synthetic ye'elimite, ) in the presence of gypsum and varying amounts of calcium hydroxide

Craig W. Hargis, Ana Paula Kirchheim, Paulo J. M. Monteiro, Ellis M. Gartner

Research output: Contribution to journalArticlepeer-review

113 Scopus citations

Abstract

Suspensions of synthetic ye'elimite (C4A3S̄) in a saturated gypsum (CS̄H2) and calcium hydroxide (CH) solution were examined in-situ in a wet cell by soft X-ray transmission microscopy and ex-situ by scanning electron microscopy. The most voluminous hydration product observed was ettringite. Ettringite commonly displayed acicular, filiform, reticulated, and stellate crystal habits. Additionally, pastes with C 4A3S̄, 15% CS̄H2, and varying amounts of CH were prepared and examined with X-ray diffraction (XRD) and isothermal calorimetry. The XRD experiments showed that increasing CH content caused more solid solution (SO4 2 -/OH-) AFm phases to form at early ages (< 1 d) and more monosulfate to form at later ages (> 1 d). Calorimetry indicated that the increased production of solid solution AFm was accompanied with an increase in the initial (< 30 min) rate of heat evolution, and increasing CH generally reduced the time till the second maximum rate of heat evolution due to the formation of ettringite and monosulfate. © 2013 Elsevier Ltd.
Original languageEnglish (US)
Pages (from-to)105-115
Number of pages11
JournalCement and Concrete Research
Volume48
DOIs
StatePublished - Jun 2013
Externally publishedYes

Fingerprint

Dive into the research topics of 'Early age hydration of calcium sulfoaluminate (synthetic ye'elimite, ) in the presence of gypsum and varying amounts of calcium hydroxide'. Together they form a unique fingerprint.

Cite this