This paper presents an experimental result on the behavior of fly ash and slag based geopolymer concrete exposed to 5% sulphate solutions for 3.5 months of G30 and G50 which are equivalent to M30 and M50 grades respectively. The test specimens were cast and after one day rest period, half of the specimens were cured in an oven at 60°C for 24 hours and the remaining period cured in sun light until the testing is done and remaining half of the specimens were ambient cured. After 28 days the specimens were immersed in sulphates such as Na2SO4 and MgSO4 for 15, 45, 75 and 105 days then tested on 15th, 45th, 75th and 105th day according to codal procedures and the results are compared with the controlled concrete. From the test results, it is observed that the geopolymer concrete has better resistance to sulphates attack than controlled concrete.

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International Journal of Civil Engineering and Technology (IJCIET)
Volume 10, Issue 02, February 2019, pp. 510-518, Article ID: IJCIET_10_02_051
Available online at http://www.iaeme.com/ijciet/issues.asp?JType=IJCIET&VType=10&IType=02
ISSN Print: 0976-6308 and ISSN Online: 0976-6316
© IAEME Publication Scopus Indexed
STUDIES ON THE BEHAVIOUR OF SULPHATE
ATTACK RESISTANCE OF LOW CALCIUM
FLY ASH AND SLAG BASED GEOPOLYMER
CONCRETE
Dr.T Srinivas
Department of Civil Engineering, GRIET, Hyderabad –500090
Dr. N V Ramana Rao
Department of Civil Engineering, JNTUH, Hyderabad –500085
ABSTRACT
This paper presents an experimental result on the behavior of fly ash and slag based
geopolymer concrete exposed to 5% sulphate solutions for 3.5 months of G30 and G50
which are equivalent to M30 and M50 grades respectively. The test specimens were
cast and after one day rest period, half of the specimens were cured in an oven at 60°C
for 24 hours and the remaining period cured in sun light until the testing is done and
remaining half of the specimens were ambient cured. After 28 days the specimens were
immersed in sulphates such as Na2SO4 and MgSO4 for 15, 45, 75 and 105 days then
tested on 15th,
45th
, 75th
and 105th
day according to codal procedures and the results
are compared with the controlled concrete. From the test results, it is observed that the
geopolymer concrete has better resistance to sulphates attack than controlled concrete.
Keywords: Fly Ash, Geopolymer Concrete, GGBS, Oven Curing, Sulphate Attack
Cite this Article: Dr.T Srinivas and Dr. N V Ramana Rao, Studies On The Behaviour
Of Sulphate Attack Resistance Of Low Calcium Fly Ash And Slag Based Geopolymer
Concrete International Journal of Civil Engineering and Technology,10(2),2019,pp.
http://www.iaeme.com/ijciet/issues.asp?JType=IJCIET&VType=10&IType=02
1. INTRODUCTION
Geopolymer is an inorganic polymer. Joseph Davidovits in 1979 proposed that an alkaline
liquid could be used to react with silicon (Si) and aluminum (Al) as source material of
geological origin or with byproduct materials such as fly ash, GGBS and rice husk ash etc; to
produce binders. Since the chemical reaction that is taking place in this case is a polymerization
process and the precursors are of geological origin, these binders were named as ‘Geopolymer’
2. MATERIALS

2. Studies on The Behaviour of Sulphate Attack Resistance of Low Calcium Fly Ash and Slag Based
Geopolymer Concrete
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2.1. Ordinary Portland Cement
The cement thus procured was tested for physical properties in accordance with the IS: 4031-
1968 and found to be conforming various specifications of IS 12629-1987.
2.2. Fine Aggregate
The physical properties of fine aggregate like specific gravity, bulk density, gradation and
fineness modulus are tested in accordance with IS: 2386. Grain size distribution of sand shows
it is close to Zone II of IS 383-1970.
2.3. Coarse Aggregate
The crushed angular aggregate of 20mm maximum size obtained from the local crushing plants
is used as coarse aggregate in the present study. The physical properties of coarse aggregate
such as specific gravity, bulk density, flakiness and elongation index are tested in accordance
with IS: 2386-1963.
2.4. Ground Granulated Blast Furnace Slag
Ground Granulated Blast Furnace Slag (GGBS) is a by-product of the steel industry. About
15% by mass of binders was replaced with GGBS.
2.5. Water
Water free from chemicals, oils and other forms of impurities is to be used for mixing of
concrete as per IS: 456:2000.
2.6. Constituents of Geopolymer
2.6.1. Source Materials
Any material that contains mostly Silicon (Si) and Aluminium (Al) in amorphous form is a
possible source material for the manufacture of geopolymer. Several minerals and industrial
by-product materials have been investigated in the past. Low calcium fly ash (ASTM Class F)
is preferred as a source material than high calcium (ASTM Class C) fly ash.
2.6.2. Alkaline Activators
The most common alkaline activator used in geopolymerisation is a combination of sodium
hydroxide (NaOH) and sodium silicate (Na2SiO3).
2.7. Superplasticiser
High range water reducing super plasticizer PCE based (Master Glenium B233) for G50 and
Naphthalene based for G30 was used in the mixtures at the rate of 1.5% and 1% by weight of
fly ash respectively to improve the workability.
3. EXPERIMENTAL INVESTIGATION
3.1. General

3. Dr.T Srinivas and Dr. N V Ramana Rao
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This paper presents experimental results on the behavior of fly ash and slag based geopolymer
concrete exposed to 5% sulphate solutions for up to 3 months of G30 and G50 which are
equivalent to M30 and M50 grades respectively. The alkaline solution used for the present
study is combination of sodium silicate (Na2Sio3) and sodium hydroxide. The ratio of Na2SiO3
to NaOH is 2.5 and SiO2 to Na2O is 2.09 has been used since the compressive strength is
maximum at these ratios. In case of geopolymer concrete the cubes of size
100mm×100mm×100mm were cast and after one day rest period, half of the specimens were
cured in an oven at 60°C (OC) for 24 hours and the remaining period cured in sun light until
the specimens immersed in sulphates and remaining half of the specimens were ambient cured
(AC) and in controlled concrete conventional method is adopted for preparing the same size of
cubes and kept under water for curing (NC). After 28 days the specimens were immersed in
sulphates such as Na2SO4 and MgSO4 for 15, 45, 75 and 105 days then the sulphate attack
resistance in terms of loss of compressive strengths and loss of weights of various grades of
controlled and geopolymer concrete exposed to 5% concentrations of Na2SO4 and MgSO4
sulphates. Acid Durability Factors (ADFs) and Acid Attack Factors (AAFs) of controlled and
geopolymer concrete exposed to 5% concentrations of various sulphates are also evaluated to
determine their resistance to sulphate attack and the obtained results have been studied and
compared.
3.2. Mixing and Casting of Geopolymer Concrete
Geopolymer concrete can be manufactured by adopting the conventional concrete techniques
used in the manufacture of Portland cement concrete. In the laboratory, the fly ash and the
aggregates were first mixed together dry in a pan mixer for about three minutes. The alkaline
liquid was mixed with the super plasticizer and extra water if any. The liquid component of the
mixture was then added to the dry material and the mixing continued usually for another four
minutes. The fresh concrete was cast and compacted by the usual methods used in the case of
Portland cement concrete. The workability of the fresh concrete was measured by means of the
conventional slump test.
4. TEST RESULTS
4.1. Weight Loss and Residual Compressive Strength
The loss of weight and compressive strength of controlled and geopolymer concrete in
percentage when it is exposed to 5% concentration of Na2SO4 and MgSO4 solutions for various
curing methods are given in Figs 1 to 4.

4. Studies on The Behaviour of Sulphate Attack Resistance of Low Calcium Fly Ash and Slag Based
Geopolymer Concrete
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Figure 1 Weight Loss in Percentage of Controlled (M30) & Geopolymer Concrete (G30) when
immersed in 5% concentrations of various Sulphates and Curing methods
Figure 2 Weight Loss in Percentage of M50 & G50 when immersed in 5% concentrations of various
Sulphates and Curing methods
0
0.2
0.4
0.6
0.8
1
0 15 30 45 60 75 90 105
NC MgSO4
NC Na2SO4
OC MgSO4
OC Na2SO4
AC MgSO4
AC Na2SO4
Immersion Period in Days
LossofWeightin%
M 30 & G 30
0
0.2
0.4
0.6
0.8
1
0 15 30 45 60 75 90 105
NC MgSO4
NC Na2SO4
OC MgSO4
OC Na2SO4
AC MgSO4
AC Na2SO4
Immersion Period in Days
LossofWeightin%
M 50 & G 50

5. Dr.T Srinivas and Dr. N V Ramana Rao
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Figure 3 Compressive Strength Loss in Percentage of M30 & G30 when immersed in 5%
concentrations of various Sulphates and Curing methods
Figure 4 Compressive Strength Loss in Percentage of M50 & G50 when immersed in 5%
concentrations of various Sulphates and Curing methods
4.2. Acid Durability Factors (ADFs) and Acid Attack Factors (AAFs)
4.2.1. Acid Durability Factors
The “Acid Durability Factors” (ADFs) can be designed as follows.
ADF = Sr (N/M)
where, Sr = relative strength at N days, (%)
N = number of days at which the durability factor is needed
M = number of days at which the exposure is to be terminated
0
4
8
12
16
20
0 15 30 45 60 75 90 105
NC MgSO4
NC Na2SO4
OC MgSO4
OC Na2SO4
AC MgSO4
AC Na2SO4
Immersion Period in Days
LossofCompressiveStrengthin%
M 30 & G 30
0
3
6
9
12
15
0 15 30 45 60 75 90 105
NC MgSO4
NC Na2SO4
OC MgSO4
OC Na2SO4
AC MgSO4
AC Na2SO4
Immersion Period in Days
LossofCompressiveStrengthin%
M 50 & G 50

6. Studies on The Behaviour of Sulphate Attack Resistance of Low Calcium Fly Ash and Slag Based
Geopolymer Concrete
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Acid attack test was terminated at 105 days. So, M is 105 in this case
4.2.2. Acid Attack Factors
The extent of deterioration at each corner of the struck face and the opposite face is measured
in terms of the solid diagonals (in mm) for each of the two cubes and the “Acid Attack Factors”
(AAFs) per face is calculated as follows.
AAF = (Loss in mm on eight corners of each of 2 cubes) / 4
Figure 5 Acid Durability Factors (ADFs) of M30 & G30 when immersed in 5% concentrations of
various Sulphates and Curing methods
Figure 6 Acid Durability Factors (ADFs) of M50 & G50 when immersed in 5% concentrations of
various Sulphates and Curing methods
0
30
60
90
0 15 30 45 60 75 90 105
NC MgSO4
NC Na2SO4
OC MgSO4
OC Na2SO4
AC MgSO4
AC Na2SO4
Immersion Period in Days
ACidDuarabilityFactors(ADFs)
0
30
60
90
0 15 30 45 60 75 90 105
NC MgSO4
NC Na2SO4
OC MgSO4
OC Na2SO4
AC MgSO4
AC Na2SO4
Immersion Period in Days
ACidDuarabilityFactors(ADFs)

7. Dr.T Srinivas and Dr. N V Ramana Rao
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Figure 7 Acid Attack Factors (AAFs) of M30 & G30 when immersed in 5% concentrations of various
Sulphates and Curing methods
Figure 8 Acid Attack Factors (AAFs) of M50 & G50 when immersed in 5% concentrations of various
Sulphates and Curing methods
Figs 5 to 8 shows the Acid Durability Factors (ADFs) and Acid Attack Factors (AAFs) of
controlled and geopolymer concrete specimens exposed to 5% concentration of Na2SO4 and
MgSO4 solutions for various curing methods. From the graphs it is observed that the Acid
Durability Factors (ADFs) increased, whereas the Acid Attack Factors (AAFs) decreased for
geopolymer concrete when it is compared with controlled concrete for all the grades and in
both the sulphate solutions such as Na2SO4 and MgSO4.
0
0.2
0.4
0.6
0.8
1
0 15 30 45 60 75 90 105
NC MgSO4
NC Na2SO4
OC MgSO4
OC Na2SO4
AC MgSO4
AC Na2SO4
Immersion Period in Days
ACidAttackFactors(AAFs)
0
0.2
0.4
0.6
0.8
1
0 15 30 45 60 75 90 105
NC MgSO4
NC Na2SO4
OC MgSO4
OC Na2SO4
AC MgSO4
AC Na2SO4
Immersion Period in Days
ACidAttackFactors(AAFs)

8. Studies on The Behaviour of Sulphate Attack Resistance of Low Calcium Fly Ash and Slag Based
Geopolymer Concrete
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5. CONCLUSIONS
1. The following specific conclusions can be drawn from the present experimental
investigation
2. When the specimens are exposed to magnesium and sodium sulphates, the percentage
loss of compressive strength and weights are increased as the immersion period
increases for all the grades of controlled and geopolymer concrete.
3. The original compressive strength of M30 and M50 is 38.62MPa and 58.42MPa
respectively then it lost by 4.67 to 16.42%, whereas in geopolymer concrete which is
originally 38.45MPa and 59.75MPa lost by 3.19 to 12.03% when it is exposed to
sodium sulphate for a period of 15 days to 105 days.
4. The loss of compressive strength of controlled concrete specimens when exposed to
magnesium sulphate is in the range of 5.58 to 18.2%, where as it is about 3.44 to 12.52%
in case of geopolymer concrete. Thus, geopolymer concrete is more resistant than
controlled concrete.
5. The loss of weight of controlled concrete specimens when exposed to sodium and
magnesium sulphates is more than that of geopolymer concrete. Therefore, it can be
said that geopolymer concrete has more dimension stability than controlled concrete.
6. It can be inferred that geopolymer concrete is more durable in terms of ‘Acid Durability
Factors’ and is less attacked in terms of ‘Acid Attack Factors’ than controlled concrete
at all the ages for all grades and can perform better in severe aggressive environments
due to its high impermeability and alkalinity of concrete mass.
7. It can be concluded that the magnesium sulphate environment is more severe than
sodium sulphate, since the strength & weight loss are more and also the specimens
received white deposits on the surfaces which gradually transformed from soft and
flaky shape to hard and rounded shape during exposure to magnesium sulphate
compared to sodium sulphate solution.
8. It is observed that the loss of compressive strengths and weights are decreased as the
grade of concrete is increased in both controlled and geopolymer concrete.
REFERENCES
[1] Davidovits, J., (1994), Properties of geopolymer cements, Proceedings of first International
conference on alkaline cements and concretes, 1, SRIBM, Kiev, Ukraine, pp 131-149.
[2] Bakharev, T., (2005(b)), Durability of geopolymer materials in sodium and magnesium
sulphate solutions, Cement and Concrete Research, 35, pp 1233-1246.
[3] Suresh Thokchom, Dr. Partha Gosh and Dr. Somnath Gosh, (2009), Acid resistance of fly
ash based geopolymer mortars, International Journal of Recent Trends in Engineering, 1(6),
pp 36-40.
[4] Rangan, B.V., (2008), Mix design and production of fly ash based geopolymer concrete,
Indian Concrete Journal, 82(5), 7 - 15.
[5] Rajamane, N. P, Nataraja M. C, Dattatreya, J. K, Lakshamanan, N and Sabitha, D, (2012),
Sulphate resistance and eco-friendliness of geopolymer concrete, The Indian Concrete
Journal, Jan., pp 13-22.
[6] Hardjito, D., Wallah, S.E., Sumajouw, D.M.J., and Rangan, B.V., (2004), On the
development of fly ash based Geopolymer concrete, ACI Materials Journal, 101(52), pp
467-472.

9. Dr.T Srinivas and Dr. N V Ramana Rao
http://www.iaeme.com/IJCIET/index.asp 518 editor@iaeme.com
[7] T.Srinivas and N.V.Ramana Rao, “Investigation on mechanical properties of low calcium
fly ash and slag based geopolymer concrete”, International Journal of Latest Trends in
Engineering and Technology (IJLTET), Vol 7, issue 3, June 2016, Summer Special Issue,
pp 223-234.
[8] IS:383-1970, Specification for coarse and fine aggregates from natural sources for concrete,
Bureau of Indian standards, New Delhi.
[9] IS:516-1959, Methods of test for strength of concrete, Bureau of Indian standards, New
Delhi.
[10] Kolli Ramujee and Dr.M.Potharaju, “Development of Mix Design for Low Calcium based
Geopolymer concrete in Ordinary, Standard and High Strength Grades”, ICI Journal, July-
September, 2013, pp 29-34.
[11] Srinivasa Reddy V et al.,” A Biological Approach to Enhance Strength And Durability In
Concrete Structures”, International Journal of Advances in Engineering & Technology,
September, 2013, Vol. 4, Issue 2, pp 392-399.
[12] T.Srinivas and N.V.Ramana Rao, “Development and Optimization of Mix Design of Low
Calcium Fly Ash and Slag Based Geopolymer Concrete for Standard Grade”, IOSR Journal
of Mechanical and Civil Engineering (IOSR-JMCE), Volume 13, Issue 4 Ver. III (Jul. -
Aug. 2016), pp 39-47.
[13] Experimental Study on Coir Fibre Reinforced Flyash Based Geopolymer Concrete With
12m & 10m Molar Activator
[14] Experimental Study on Coir Fibre Reinforced Flyash Based Geopolymer Concrete With
12m & 10m Molar Activator
[15] Experimental Study on Coir Fibre Reinforced Flyash Based Geopolymer Concrete With
12m Molar Activator
[16] Experimental Study on Plastic Fiber Reinforced Flyash Based Geopolymer Concrete