Ceramics-Silikáty 55, (1) 68 - 78 (2011) |
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EFFECTS OF BLAST-FURNACE SLAG ON NATURAL POZZOLAN-BASED GEOPOLYMER CEMENT
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Allahverdi Ali 1, Kani Ebrahim Najafi 2, Yazdanipour Mahshad 1
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1 Cement Research Center, School of Chemical Engineering,
Iran University of Science and Technology, Narmak 1684613114, Tehran, Iran
2 School of Chemical, Petroleum, and Gas Engineering,
Semnan University, Semnan, 35195-363, Iran
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Keywords: Geopolymer cement, Natural Pozzolan, Granulated blast furnace Slag, Mechanical Properties, Microstructure
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A number of geopolymer cement mixes were designed and produced by alkali-activation of a pumice-type natural pozzolan.
Effects of blast-furnace slag on basic engineering properties of the mixes were studied. Different engineering properties of
the mixes such as setting times and 28-day compressive strength were studied at different amounts of blast-furnace slag,
sodium oxide content, and water-to-cement ratio. The mix comprising of 5 wt.% blast-furnace slag and 8 wt.% Na₂O with
a water-to-dry binder ratio of 0.30 exhibits the highest 28-day compressive strength, i.e. 36 MPa. Mixes containing 5 wt.%
of ground granulated blast furnace slag showed the least efflorescence or best soundness. Laboratory techniques of X-ray
diffractometry (XRD), fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were utilized
for characterizing a number of mixes and studying their molecular and micro-structure. Investigations done by scanning
electron microscopy confirm that smaller blast-furnace slag particles react totally while the larger ones react partially with
alkaline activators and contribute to the formation of a composite microstructure. |
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