Microstructural Aspects of Zeolite Formation in Alkali Activated Cements Containing High Levels of Fly Ash

1994 ◽  
Vol 370 ◽  
Author(s):  
A.R. Brough ◽  
A. Katz ◽  
T. Bakharev ◽  
G-.K. Sun ◽  
R.J. Kirkpatrick ◽  
...  
Keyword(s):  
Fly Ash ◽  
Substantial Effect ◽  
Ion Concentration ◽  
Microstructure Development ◽  
Waste Solution ◽  
High Sodium ◽  
Strength Evolution ◽  
Zeolite Formation ◽  
Alkali Activated

AbstractWasteforms made by reaction at elevated temperature of a highly alkaline simulated low-level nuclear waste solution, having high sodium ion concentration, with a cementitious blend high in fly ash have been studied. Significant formation of Na-P1 zeolite (gismondine framework) and of a sodalite occurred. The time evolution of the crystalline phases over the first 28 days is reported for both adiabatic and isothermal curing, and the role of these phases in microstructure development is discussed. The level of carbonate ions in solution was found to have a substantial effect on strength evolution and chemistry.

scholarly journals Observations on the rheological response of alkali activated fly ash suspensions: the role of activator type and concentration

2014 ◽  
Vol 53 (10-11) ◽  
pp. 843-855 ◽  
Author(s):  
Kirk Vance ◽  
Akash Dakhane ◽  
Gaurav Sant ◽  
Narayanan Neithalath
Keyword(s):  
Fly Ash ◽  
Rheological Response ◽  
Alkali Activated

scholarly journals Role of Curing Conditions and Precursor on the Microstructure and Phase Chemistry of Alkali-Activated Fly Ash and Slag Pastes

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1918
Author(s):  
Marija Nedeljković ◽  
Bahman Ghiassi ◽  
Guang Ye
Keyword(s):  
Fly Ash ◽  
Analytical Techniques ◽  
Limited Information ◽  
Reaction Products ◽  
Curing Conditions ◽  
X Ray ◽  
Phase Recognition ◽  
Phase Chemistry ◽  
Alkali Activated

Understanding the role of curing conditions on the microstructure and phase chemistry of alkali-activated materials (AAMs) is essential for the evaluation of the long-term performance as well as the optimization of the processing methods for achieving more durable AAMs-based concretes. However, this information cannot be obtained with the common material characterization techniques as they often deliver limited information on the chemical domains and proportions of reaction products. This paper presents the use of PhAse Recognition and Characterization (PARC) software to overcome this obstacle for the first time. A single precursor (ground granulated blast-furnace slag (GBFS)) and a binary precursor (50% GBFS–50% fly ash) alkali-activated paste are investigated. The pastes are prepared and then cured in sealed and unsealed conditions for up to one year. The development of the microstructure and phase chemistry are investigated with PARC, and the obtained results are compared with independent bulk analytical techniques X-ray Powder Fluorescence and X-ray Powder Diffraction. PARC allowed the determination of the type of reaction products and GBFS and FA’s spatial distribution and degree of reaction at different curing ages and conditions. The results showed that the pastes react at different rates with the dominant reaction products of Mg-rich gel around GBFS particles, i.e., Ca-Mg-Na-Al-Si, and with Ca-Na-Al-Si gel, in the bulk paste. The microstructure evolution was significantly affected in the unsealed curing conditions due to the Na+ loss. The effect of the curing conditions was more pronounced in the binary system.

scholarly journals Role of Fly Ash on Strength and Microstructure Development in Blended Cement Stabilized Silty Clay

2009 ◽  
Vol 49 (1) ◽  
pp. 85-98 ◽  
Author(s):  
Suksun Horpibulsuk ◽  
Runglawan Rachan ◽  
Yuttana Raksachon
Keyword(s):  
Fly Ash ◽  
Blended Cement ◽  
Silty Clay ◽  
Microstructure Development
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