Geopolymer Concrete for Paving: An Eco-Friendly Alternative

International Journal of Civill Engineering
E
and Technology (IJCIET)
Volume 8, Issue 7, July 2017, pp.
pp 886–892, Article ID: IJCIET_08_07_095
Available online at http://http://ww
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VType=8&IType=7
ISSN Print: 0976-6308 and ISSN
N Online: 0976-6316
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Scopus Indexed
GEOPOLY
YMER CONCRETE AN E
ECOFRIENDLY ALTERNATIVE
A
TO PORT
RTLAND
CEMENT P
PAVING GRADE CONCR
CRETE
Girish M. G
Assistantt Professor,
P
Department of Civil Engineering,,
Manipal Institutee of
o Technology, Manipal University, Karnatak
aka, India
Kiran K. Shetty
Profe
fessor, Department of Civil Engineering,
Manipal Institutee of
o Technology, Manipal University, Karnatak
aka, India
Raja Rao A
PG Student,
Stu
Department of Civil Engineering,
Manipal Institutee of
o Technology, Manipal University, Karnatak
aka, India
ABSTRACT
The current generation
ion of “Sustainable development” demands the
th new concrete
which uses the less natura
ral resource, energy as well as generates less
les CO2, without
compromising on strength
th and durability aspects. In this context rese
search works on
geopolymer concrete pre
repared from conventional alkali-activatorr solutions like
sodium hydroxide and so
sodium silicate curable at ambient temperat
rature is gaining
momentum now-a-days. In this paper, the paste phase and solid phas
ase properties of
geopolymer concrete conta
ntaining quarry dust and sand as fine aggrega
gate, suitable for
rigid pavement applicatio
tion, curable at ambient temperature are the points of
discussion.The targeted compressive
co
strength of 40MPa was achieved ssoon after seven
days of air curing and maaximum strength attained in 28 days is nearl
rly 62MPa. Both
the compressive strength aand the flexural strength were within the acce
cceptance limit of
paving grade concrete.
Key words: Alkaline activ
ivators,Geopolymer concrete, Fly-ash, GGBS,
S, Quarry dust
Cite this Article: Girish M.
M G, Kiran K.Shetty and Raja Rao A, Geopo
polymer Concrete
an Eco-Friendly Alternativ
ive to Portland Cement Paving Grade Concret
rete. International
Journal of Civil Engineerin
ing and Technology, 8(7), 2017, pp. 886–892.
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IET/issues.asp?JType=IJCIET&VType=8&ITyp
ype=7
1. INTRODUCTION
Concrete is the most consum
med material next to water in the world. Too live, how water is
essential, similarly for shelter
er concrete building is important in this era.. T
The manufacture of
cement is considered to be hig
highly energy intensive next to steel and alum
minium. The process
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Girish M. G, Kiran K.Shetty and Raja Rao A
of manufacturing of 1000kg of Portland clinker directly generates over a 500kg of chemicalCarbon dioxides, and nearly another 500kg of Carbon dioxide comes from the combustion of
carbon-fuel[1]. The only exceptions are so-called ‘blended cement', using such ingredients as
coal fly-ash, where the emissions of carbon dioxides are slightly suppressed, by a maximum
of 10-15%[1].Geopolymer cement (GC) does not rely on calcium carbonate and generate a
very minimal amount of CO2 for its manufacture, i.e. a reduction in the range of 40% to 8090% [1].
The geopolymer cement is formed by polymerization process which involves the reaction
between an aluminosilicate source material such as fly-ash, GGBS, etc. with an alkaline
activator solutions. The process results in the creation of a network of a tetrahedral chain of
SiO4 and AlO4 to shared oxygen atoms alternatively [2]. Hardening of GC takes place through
polycondensation of potassium oligo (sialate-siloxo) into potassium poly (sialate-siloxo)
cross-linked network [1]. The GC, so formed binds the aggregates and inert materials to form
a matrix called geopolymer concrete (GPC). Present days, lots of researchesare being carried
out on the utilisation of industrial by-product such as fly-ash, GGBS, silica fumes, metakaolin
as an aluminosilicate precursor material for geopolymers[3]. The alkaline liquids used in the
production of GC mainly are of soluble alkali metals that are usually sodium or potassium
based. The most commonly used alkaline liquid is the combination of Sodium Hydroxide
(NaOH) and Sodium Silicate (Na2SiO3) or Potassium Hydroxide (KOH) and Potassium
Silicate (K2SiO3) [4].
The molarity and molar ratio of alkaline solution, water to binder ratio, plasticiser and
curing temperature is found to have a profound effect on the fresh and hardened state of
geopolymer concrete [5]. The increase in molarity of NaOH solution from 8M to 14M and
molar ratio increases the strength and decreases the workability of the concrete respectively.
The increase of super plasticizer content and the alkali concentration improves the interfacial
transition zone (ITZ) and microstructure of GPC[6]. The presence of additional water
exceeding 15% causes bleeding, segregation and reduced the compressive strength of the
concrete[7].
The geopolymer concrete, in future, can become a viable alternative to OPC as a binding
material in mass concreting applications. In recent times researches have been carried out
across many locations of the world to investigate the potentials of GPC for structural
applications. However, little is known as for as its applications in the field of the highway
pavements are concerned. In this paper, attempts are made to explore the possibilities of using
GPC as a paving grade concrete. The production of GPC is carried out using the OPC
concrete production technology methods.
2. MATERIALS AND THEIR PROPERTIES
2.1. Fly-ash
Fly ash from Raichur Thermal Power Station (RTPS) located in Karnataka, India is used as
one of the precursors. According to IS: 3812-2000 [8], it is classified as Class-F fly ash.
Specific gravity is measured as 2.05 according to IS:1727-1967[9]. Pozzolanic activity index
with Portland cement is 74.22% and Blaine’s surface area of 3225 cm2/gm.
2.2. Aggregates
Locally available clean river sand and quarry dust were used as fine aggregates. The F.A
belongs to grading Zone II as per IS: 383-1970[10],with the specific gravity,of 2.64 and
fineness modulus of 2.935.
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Geopolymer Concrete an Eco-Friendly Alternative to Portland Cement Paving Grade Concrete
The quarry dust with specific gravity 2.62 and fineness modulus 2.847obtainedin the
vicinityis used in the current study Crushed aggregate of 20 mm down sizehaving specific
gravity 2.68 and fineness modulus 6.969is utilised as coarse aggregate.
2.3. Alkaline Solution
The commonly used alkaline activators in Geopolymer concrete are sodium hydroxide and
sodium silicate solutions. Sodium silicate solution (A53) is obtained from a local factory, and
it is composed of Na2O- 13.54%, SiO2- 32.46% and H2O- 54.0%. Sodium hydroxide used is
of analytical grade and is of 97% purity.
2.4. Water
Potable water conforming to IS: 456-2000 [11]is used in all mixes. And it is free from salts
and other organic impurities. The water content in GPC is the combined water present in the
alkali solution. The amount of water in Silicate solution is found out by chemical analysis.
2.5. Ground Granulated Blast Furnace Slag (GGBS)
GGBS was obtained from Jindal Steel Works (JSW) Bellary, Karnataka. The specific gravity
of GGBS was found to be 2.88.
2.6. Super Plasticizer
Conplast SP500 conforming to IS: 9103-1999, is based on Sulphonated Napthalene Polymers
and is supplied as a brown liquid instantly dispersible in water. The specific gravity was
found to be 1.26.
3. MIX DESIGNS
The composition of the geopolymer mixes used in the present investigation is given in the
Table1. The NaOH solution of 12M concentration is preferred in this study. The NaOH
solution was prepared 24 hours before the mixing. Mix M1 and M2 are more or less identical
in composition except that, in mix M2, sand is replaced by quarry dust by same amount. Mix
M3 also has quarry dust in place of sand as fine aggregate. The quantity of coarse aggregate
used in M3 is slightly higher than M1 and M2.
Table 1 Composition of Mixes
Materials
Fly Ash
GGBS
NaOH soln. (L/m3)
Na2SiO3 soln. (L/m3)
S.P (L/m3)
F.A (quarry dust)
F.A (river sand)
C.A
Water (L/m3)
Na2SiO3/NaOH
Water to GPS ratio
Alkaline to Binder ratio
M1
(kg/m3)
330
220
45.15
112.88
16.5
735
870
24.75
2.5
0.19
0.29
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888
M2
(kg/m3)
330
220
45.15
112.88
16.5
735
870
41.8
2.5
0.213
0.29
M3
(kg/m3)
237
158
45.15
112.88
11.85
555
1290
39.5
2.5
0.28
0.40
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Girish M. G, Kiran K.Shetty and Raja Rao A
4. EXPERIMENTAL RESULTS AND DISCUSSIONS
4.1. Fresh Properties for Paving Grade Concrete
The target slump in the range 6 to 8 inches, spread in the range 11 to 13 inches and
compaction factor > 95% was recognised as standard to define the fresh state properties of
paving grade geopolymer concrete. Figure 1 represents the slump test and Figure 2 represents
the spread test. The results of the slump test, compaction factor test and spread test are
presented in Table 2. The compaction factor values of all the mixes were comparable to the
set standards. The slump and spread values of mixes M1 and M2 were close to adopted
standards. However, slump and spread values of mix M3 are found to be not within the range.
This is due to slightly increase in quantity of coarse aggregate and reduction quarry of dust
which caused stiffening of the paste and loss of mobility.
Table 2 Results of slump cone and spread tests
Mixes
Slump (inches)
Spread (inches)
M1
M2
M3
9.0
8.5
5.0
16.5
15.5
9.0
Figure 1 Slump
Compaction
Factor (%)
98
96.5
95.6
Figure 2 Spread test
4.2. Density
The density values of GPC mixes were in the range of 2300 to 2500 kg/m3 which is found to
be similar to thedensity of OPC concrete.
4.3. Compressive Strength
The compression strength test values of GPC cube specimens of size 100x100x100 mm of
three mixes, when tested under compression load as per IS: 516-1959 [13]is presented in
Table3, and same is graphically depicted in Figure.3.
Table 3 Compressive strength of mixes
Mix
M1
M2
M3
7 days (MPa)
54.71
45.23
40.01
14 days (MPa)
58.17
46.89
40.82
28 days (MPa)
62.15
49.91
55.03
Compressive strength values of all the mixes indicates, an incremental increase in the
strength over three ambient curing frequencies. This is because of the pozzolanic activity of
fly ash which supplies Si and Al, GGBS rich in Ca supplies enough Ca for the reaction and
the alkaline solution which binds the binder contents. All the three mixes achieved an average
compressive strength of more than 40MPa in 7 days. As per Indian Road Congress code
specification [14, 15], a 28days compressive strength of 40MPa is viewed as min.
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compressive strength requirement of cement concrete for rigid pavement. This phenomenon
of early age strength gain is known to be beneficial since this can facilitate early opening of
pavement to vehicular traffic. The complete replacement of sand by quarry dust resulted in
decreasing the compressive strength of GPC. On the other hand, the excess coarse aggregate
content improved the compressive strength of GPC.
compressive strength in MPa
Compressive strength
80
60
40
7 days
20
14 days
0
28 days
M1
M2
M3
Mixes of GPC
Figure 3 Compressive strength of GPC mixes
4.4. Flexural Strength
To measure flexural strength, beams of size 100x100x500 mm were used and tested as per IS:
516-1959 specifications[13]. Results of average flexural strength test of different mixes at the
age of 28 days are given in Table 4 and shown pictorially in Figure 4. The combined stresses
due to wheel load and temperature developed in the rigid pavement should be less than
flexural strength of cement concrete used in rigid pavements [15]. Therefore the flexural
strength of concrete is known to be of prime importance. The test results show that all the
three mixes possessed a flexural strength higher than min. required i.e. 4.42MPa for paving
grade concrete of compressive strength 40MPa. Mix M1 had the highest flexural strength then
followed by M3 and M2 being the least.
Table 4 Flexural strength test results.
Mix
M1
28 days (MPa)
5.30
M2
M3
4.92
5.10
Flexural Strength in MPa
Flexural strength
5
4
3
2
1
0
M1
M2
M3
Mixes of GPC
Figure 4 Flexural strength of GPC mixes
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5. CONCLUSIONS
The study aimed at developing a geopolymer concrete suitable for rigid pavement application.
The study comprised of examining the fresh and hardened state behaviour of three different
mixes of geopolymer concrete. Among the mixes; mix M1 contained sand as fine aggregate,
mix M2 had quarry dust as fine aggregate and mix M3 was having more courseaggregate
content along with quarry dust when compare to other two mixes.
The following conclusions are arrived from the studies:•
The fresh state properties of the GPC indicated that the slump and spread values were in the
close proximity of assumed standards except for the mix M3. Thus it can be concluded that the
developed GPC can be adopted for fixed form paving.
•
The compressive strength of GPC obtained was in the range of 40-60MPa which is more than
the target strength. The mixes gained strength gradually over the period of times of curing.
This is due to the pozzolanic action of fly ash. All the three mixes acquired a target strength of
40MPa in 7 days of curing. Thus it can be concluded the GPC may facilitate the early opening
of road to traffic. The complete replacement of sand by quarry dust resulted in a reduction of
compressive strength of GPC. Whereas the GPC containing a combination of more quantity of
coarse aggregate and the quarry dust produced better compressive strength.
•
The flexural strength of GPC is found to be significantly more than the target strength. Hence,
it can be concluded that the GPC can become a practicable alternative to conventional cement
concrete pavement.
REFERENCES
[1]
Joseph Davidovits, “Geopolymer cement”, a review, Institut Geopolymere, Saint-Quentin,
France, www.geopolymer.org, 2013.
[2]
Joseph Davidovits, Properties of Geoploymer Cements, First International Conference on
Alkaline Cements and Concretes, Scientific Research Institute on Binders and Materials,
KIEV State Technical University, KIEV, Ukraine, 1994, 131-149.
[3]
Wallah, S.E. and Rangan, B.V., Low-calcium fly-ash based geopolymer concrete: longterm properties, Research Report GC 2, Faculty of Engineering Curtin University of
Technology Perth, Australia, 2006.
[4]
Rangan, B.V., Geopolymer concrete for environmental protection, The Indian Concrete
Journal, 88(4), 2014, 41-48, 50-59.
[5]
Hardjito, D. and Rangan, B.V., (2005), “Development and properties of low calcium flyash based geo-polymer concrete”, Research Report GC 1, Faculty of Engineering Curtin
University of Technology Perth, Australia
[6]
Fadhil Nuruddin, M., Samuel Demie, Fareed Ahmed, M. and Nasir Shafiq, Effect of
superplasticizer and NaOH molarity on workability, compressive strength and
microstructure properties of self-compacting Geopolymer concrete, International Journal
of Environmental, Chemical, Ecological, Geological and Geophysical Engineering, 5(3),
2011, 187-194.
[7]
Fareed Ahmed Memon, Muhd Fadhil Nuruddin, Samuel Demie and Nasir Shafiq, Effect
of superplasticizer and extra water on workability and compressive strength of selfcompacting geopolymer concrete, Research Journal of Applied Sciences, Engineering and
Technology, 4(5), 2012, 407-414.
[8]
IS 3812 (Part 1) (2013), Specification for pulverized fuel ash: Part 1 For use as pozzolana
in cement, cement mortar and concrete, Bureau of Indian Standards, New Delhi.
http://www.iaeme.com/IJCIET/index.asp
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Geopolymer Concrete an Eco-Friendly Alternative to Portland Cement Paving Grade Concrete
[9]
IS 1727-1967, Methods of test for pozzolanic materials, Bureau of Indian Standards, New
Delhi.
[10]
IS 383-1970, Specification for coarse and fine aggregate from natural sources for
concrete, Bureau of Indian Standards, New Delhi.
[11]
IS 456-2000, Plain and Reinforced Concrete - Code of Practice, Bureau of Indian
Standards, New Delhi
[12]
BS 6699-1992, Specification for ground granulated blast furnace slag for use withPortland
cement
[13]
IS 516-1959, Method of test for strength of concrete, Bureau of Indian Standards,
NewDelhi.
[14]
IRC 15-2011, Standard specifications and code of practice for construction of concrete
roads, Indian Road Congress.
[15]
IRC 58-2002, Guidelines for design of plain jointed rigid pavements for highways, Indian
Road Congress.
[16]
Balaraman R, Vinodh K.R, Nithiya R and Arunkumar S, Comparative Study of
Geopolymer Concrete in Flyash with Conventional Concrete. International Journal of
Civil Engineering and Technology, 7(4), 2016, pp.24–36.
[17]
K. Chandra Padmakar and B. Sarath Chandra Kumar, An Experimental Study on
Metakaolin and GGBS Based Geopolymer Concret. International Journal of Civil
Engineering and Technology, 8(1), 2017, pp. 544–557.
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