A Structural Investigation Relating to the Pozzolanic Activity of Rice Husk Ashes

Various factors determine the applicability of rice husk ash (RHA) as a pozzolanic material. The amount and accessibility of reactive sites is thought to be a key factor. A structural study of RHA samples in relation to their reactivity has been performed; Silica in RHA formed by burning rice husk in a laboratory furnace under continuous supply of air was characterized as a function of incineration temperature, time, and cooling regime. The characterization methods included chemical analyses, conductivity measurements, microscopic analysis, X-ray diffraction (XRD), and 29Si magic-angle spinning (MAS) nuclear magnetic resonance (NMR). In line with earlier observations, the analyses shows that the highest amounts of amorphous silica occur in samples burned in the range of 500-700°C. The 29Si NMR data allows direct identification of the reactive silanol sites in the RHA samples. De-convolution of the NMR spectra clearly shows that the quickly cooled RHA resulting from burning rice husk for 12 h at 500°C has the highest amount of silanol groups. This sample also induced the largest drop in conductivity when added to a saturated calcium hydroxide solution giving an indication of its reactivity toward lime. Therefore, this RHA is the favorable sample to be used as pozzolanic cement additive.

• Record URL:
  • https://doi.org/10.1016/j.cemconres.2007.10.004
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00088846
• Supplemental Notes:
  • Abstract reprinted with permission from Elsevier
• Authors:
  • Nair, Deepa G
  • Fraaij, A L A
  • Klaassen, Adri A K
  • Kentgens, Arno P M
• Publication Date: 2008-6

Language

• English

Media Info

• Media Type: Print
• Features: Figures; Photos; References; Tables;
• Pagination: pp 861-869
• Serial:
  • Cement and Concrete Research
  • Volume: 38
  • Issue Number: 6
  • Publisher: Elsevier
  • ISSN: 0008-8846
  • Serial URL: http://www.sciencedirect.com/science/journal/00088846

Subject/Index Terms

• TRT Terms: Binders; Cement additives; Chemical reactivity; Pozzolan; Pozzolanic action; Structural analysis
• Uncontrolled Terms: Pozzolanic materials; Rice husk ash
• Subject Areas: Highways; Materials; I32: Concrete;

Filing Info

• Accession Number: 01102990
• Record Type: Publication
• Files: TRIS
• Created Date: Jun 24 2008 7:41AM