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

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 (μ-SXRD) and SEM-EDS. Pastes with up to 80% fly ash replacement were studied. Phase maps for HVFA samples using μ-SXRD patterns prove that μ-SXRD is an effective method to identify and visualize the distribution of phases in the matrix. μ-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(I) with comparatively lower Ca/Si ratio than the one produced in PC system. Moreover, coexistence of C-S-H(I) and strätlingite 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 strätlingite in HVFA system. - Highlights: • High-volume fly ash (HVFA) paste was studied by scanning x-ray micro-diffraction. • Coexistence of C-S-H(I) and strätlingite in the HVFA system is clearly shown. • The distribution of minor phases in the HVFA system is shown. • Differences between inner and outer products of fly ash are observed by SEM-EDS.
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [1]
  1. Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States)
  2. (Turkey)
  3. School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, Ulsan 689-798 (Korea, Republic of)
  4. Civil Engineering Program, Department of Mechanical Engineering, State University of New York at Stony Brook, NY 11794 (United States)
  5. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States)
Publication Date:
OSTI Identifier:
22323142
Resource Type:
Journal Article
Resource Relation:
Journal Name: Cement and Concrete Research; Journal Volume: 59; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; DIFFRACTION; FLY ASH; MICROSTRUCTURE; MONOCHROMATIC RADIATION; PORTLAND CEMENT; SCANNING ELECTRON MICROSCOPY; SILICATES; X RADIATION