Characterization of morphology and hydration products of high-volume fly ash paste by monochromatic scanning x-ray micro-diffraction (mu-SXRD)

Bae S., MERAL Ç., Oh J., Moon J., Kunz M., Monteiro P. J.

CEMENT AND CONCRETE RESEARCH, vol.59, pp.155-164, 2014 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 59
  • Publication Date: 2014
  • Doi Number: 10.1016/j.cemconres.2014.03.001
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.155-164
  • Keywords: High-volume fly ash, Microstructure (B), C-S-H(I), Scanning transmission x-ray micro-diffraction, Stratlingite, C-S-H, CALCIUM-SILICATE-HYDRATE, HIGH-ALUMINA CEMENT, MECHANICAL-PROPERTIES, DRYING SHRINKAGE, PORTLAND-CEMENT, STRENGTH, SLAG, MICROSTRUCTURE, AL


The present study focuses on identification and micro-structural characterization of the hydration products formed in high-volume fly ash (HVFA)/portland cement (PC) systems using monochromatic scanning x-ray micro-diffraction (mu-SXRD) and SEM-EDS. Pastes with up to 80% fly ash replacement were studied. Phase maps for HVFA samples using mu-SXRD patterns prove that mu-SXRD is an effective method to identify and visualize the distribution of phases in the matrix. mu-SXRD and SEM-EDS analysis shows that the C-S-H formed in HVFA system containing 50% or more of fly ash has a similar structure as C-S-H(1) with comparatively lower Ca/Si ratio than the one produced in PC system. Moreover, coexistence of C-S-H(1) and stratlingite is observed in the system containing 80% of fly ash, confirming that the amount of alumina and silicate phases provided by the fly ash is a major factor for the formation of C-S-H(I) and stratlingite in HVFA system. (C) 2014 Elsevier Ltd. All rights reserved.