31-01-2013, 10:23 AM
MODIFIED GUIDELINES FOR GEOPOLYMER CONCRETE MIX DESIGN USING INDIAN STANDARD
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ABSTRACT
This experimental study is intended to identify the mix ratios for different grades of
Geopolymer Concrete by trial and error method. A new Design procedure was formulated for
Geopolymer Concrete which was relevant to Indian standard (IS 10262-2009). The
applicability of existing Mix Design was examined with the Geopolymer Concrete. Two kinds
of systems were considered in this study using 100% replacement of cement by ASTM class
F flyash and 100% replacement of sand by M-sand. It was analyzed from the test result that
the Indian standard mix design itself can be used for the Geopolymer Concrete with some
modification.
INTRODUCTION
Geopolymers are inorganic polymeric materials with a chemical composition similar to zeolites but
possessing an amorphous structure. Geopolymers may be seen as man-made rocks. They can be
produced by reacting solid aluminosilicates with a highly concentrated aqueous alkali hydroxide or
silicate solution. The chemistry and terminology of inorganic polymers was first discussed in detail
by Davidovits [1]. Since the first mention of the term ‘geopolymer’ by Davidovits [1],
Geopolymers form three-dimensional disordered frameworks of the tecto-aluminosilicate type with
the general empirical formula Mn[-(SiO2)z-AlO2]n.wH2O, in which n is the degree of
polycondensation, and M is predominantly a monovalent cation (K+, Na+), although Ca2+ may
replace twomonovalent cations in the structure [2].
MATERIALS USED
Cementitious material used in this Experimental programme was low calcium Flyash (ASTM
type F) [2]. The specific gravity Fly Ash was 2.3. The Specific gravity and Fineness modules
for manufactured sand were 3.1 and 2.15 respectively. The chemical composition for
cementitious material is shown in table 3. Locally available crushed granite stone aggregate of
size 20 mm passing and retained in 10 mm, was used and the specific gravity and fineness
modulus for the same are 2.6 and 6.4 as per IS: 2386- 1968 Part III. Both the Aggregates
compiled with the requirements of IS: 383-1970.Specific gravity of NaoH and Na2Sio3
solutions were 1.47 and 1.6 respectively.
CONCLUSION
· With the generic information available on geopolymers, a rigorous trial-and-error method
was adopted to develop a process of manufacturing fly ash-based geopolymer concrete
following the technology currently used to manufacture Ordinary Portland Cement
concrete. After some failures in the beginning, the trail-and-error method yielded
successful results with regard to manufacture of low-calcium (ASTM Class F) fly ashbased
geopolymer concrete.
· Geopolymer concrete is an excellent alternative solution to the CO2 producing port land
cement concrete.
· Low-calcium fly ash-based geopolymer concrete has excellent compressive strength
within a day and is suitable for structural applications [10].
· The price of fly ash-based geopolymer concrete is estimated to be about 10 to30
percent cheaper than that of Portland cement concrete.
· In this study it is observed that Compressive strength results obtained for M-sand was
nearly equal when compared to control concrete.