Properties of geopolymer from circulating fluidized bed combustion coal bottom ash


TOPÇU İ. B. , Toprak M. U.

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, cilt.528, sa.3, ss.1472-1477, 2011 (SCI İndekslerine Giren Dergi) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 528 Konu: 3
  • Basım Tarihi: 2011
  • Doi Numarası: 10.1016/j.msea.2010.10.062
  • Dergi Adı: MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
  • Sayfa Sayıları: ss.1472-1477

Özet

Compressive strength, atomic ratios and microstructure of geopolymer mortars (GM) made from circulating fluidized bed combustion (CFBC) coal bottom ash (CBA) were investigated to observe the effect of air curing at ambient temperature (AC) at 20 degrees C and 90% RH, dry curing (DC) at 80 degrees C and 40% RH for 20 h. The 28-d compressive strength of GM exposed to AC (GM-AC) and DC (GM-DC) were 26.23 and 24.14 MPa, respectively. The Si/Na atomic ratio of the main reaction product (N-A-S-H gel) was close to 1. Geopolymer gel (apparently crystalline) having low Si/Na ratio (0.5) may correspond to a more advanced or developed stage of the aluminosilicate gel. It was observed that the geopolymerization was completed before the N-A-S-H gel formed when Si/Na ratio of GM is close to 2. The color of the GM changed from pink to grey and the structure became denser with almost no pores, when the temperature increased from 400 to 800 degrees C. The N-A-S-H gel became more amorphous due to the sintering reactions attaining Si/Al and Si/Na ratios of 4.54 and 0.98, respectively. (C) 2010 Elsevier B.V. All rights reserved.