| Study of Geopolymer Type Paste and Concrete from High
Calcium Mongolian Fly Ashes |
JadambaaTemuujin*, Amgalan Minjigmaa, Tsoodol Zolzaya and Batmunkh Davaabal
pages : 157-160
DOI : 10.1080/0371750X.2014.922431 |
| Abstract |
| Geopolymer type paste and concrete have been prepared by alkali activation of Mongolian fly ashes. Ash residues of
Baganuur and Shivee ovoo lignite coals used by 4th thermal power plant of Ulaanbaatar city were used. Fly ashes
were characterized by chemical and mineralogical compositions, granulometrical test, porosity measurement and
FE-SEM as belonging to ASTM Type C. Both fly ashes contain up to 30% calcium oxide and up to 11% iron oxide by
mass. Particle size distribution revealed that the average d50 particle size of the Shivee ovoo fly ash is 14.5 m while
for Baganuur fly ash it is 20 m. Initially geopolymer pastes were prepared by addition of sodium hydroxide solution
to ash and curing at 70oC for different durations. After optimizing the preparation conditions of geopolymer pastes,
concretes were made by mixing paste with 75% coarse aggregates. The geopolymer products were characterized by
XRD, FTIR, compressive strength testing and freeze-thaw resistance method. Baganuur fly ash based geopolymer type
paste and concretes showed compressive strength over 30 MPa and freeze-thaw resistance of more than 40 cycles. |
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