Geo polymer concrete is a recently developed construction material which is environment friendly and perhaps best alternative to conventional concrete. In the present scenario, where global warming is a big issue due to Co2 emissions, no cement concrete like Geo Polymer Concrete is the big boon for construction industry. The research work carried out on Geo Polymer Concrete and documented in the present paper is a step forward in the direction to encourage the development of Geo Polymer Concrete for its wide application in construction industry. The present paper describes experimental work and analytical work pertaining to Finite Element Analysis using ANSYS software to simulate the flexural behavior of Reinforced Geo Polymer Concrete Beams. The alkaline solution used for present study was the combination of sodium silicate and sodium hydroxide solution with the varying ratio of 2.50. NaoH solids with 97 - 98% purity is purchased from commercial source and mixed with water to make solution with a concentration of 16 molarity.

1. http://www.iaeme.com/IJCIET/index.asp 211 editor@iaeme.com
International Journal of Civil Engineering and Technology (IJCIET)
Volume 7, Issue 1, Jan-Feb 2016, pp. 211-219, Article ID: IJCIET_07_01_018
Available online at
http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=7&IType=1
Journal Impact Factor (2016): 9.7820 (Calculated by GISI) www.jifactor.com
ISSN Print: 0976-6308 and ISSN Online: 0976-6316
© IAEME Publication
COMPARATIVE STUDY OF
EXPERIMENTAL AND ANALYTICAL
RESULTS OF GEO POLYMER CONCRETE
D. Annapurna
Assistant Professor, Civil Engineering Department,
University College of Engineering, Osmania University, Hyderabad, INDIA
Prof. Ravande Kishore
Professor, Civil Engineering Department, University College of Engineering,
Osmania University, Hyderabad, INDIA
M. Usha Sree
P.G. Scholar, Civil Engineering Department,
University College of Engineering, Osmania University, Hyderabad, INDIA
ABSTRACT
Geo polymer concrete is a recently developed construction material which
is environment friendly and perhaps best alternative to conventional concrete.
In the present scenario, where global warming is a big issue due to Co2
emissions, no cement concrete like Geo Polymer Concrete is the big boon for
construction industry. The research work carried out on Geo Polymer
Concrete and documented in the present paper is a step forward in the
direction to encourage the development of Geo Polymer Concrete for its wide
application in construction industry. The present paper describes
experimental work and analytical work pertaining to Finite Element Analysis
using ANSYS software to simulate the flexural behavior of Reinforced Geo
Polymer Concrete Beams. The alkaline solution used for present study was the
combination of sodium silicate and sodium hydroxide solution with the varying
ratio of 2.50. NaoH solids with 97 - 98% purity is purchased from commercial
source and mixed with water to make solution with a concentration of 16
molarity. The standard test specimens viz., cube, cylinder and prism were cast
to understand compressive strength, flexural strength, stress-strain behavior,
Poisson’s ratio. These properties are incorporated for modeling the flexural
behavior of Reinforced Geo Polymer Concrete Beams using ANSYS software,
which will simulate the load-deflection behavior, crack pattern, ultimate load
etc. The model thus developed is validated using the data generated during
experimental investigations on Reinforced Geo Polymer Concrete Beams in
flexure. The results of theoretical investigations match closely with that of

2. D. Annapurna, Prof. Ravande Kishore and M. Usha Sree
http://www.iaeme.com/IJCIET/index.asp 212 editor@iaeme.com
results obtained from experimental work, thus making the developed model
useful for predicting the flexural behavior of Reinforced Geo Polymer Concrete
Beams.
Key words: Geo Polymer Concrete, Fly Ash, Molarity, Sodium Silicate,
Sodium Hydroxide, ANSYS.
Cite this Article: D. Annapurna, Prof. Ravande Kishore and M. Usha Sree,
Comparative Study of Experimental and Analytical Results of Geo Polymer
Concrete, International Journal of Civil Engineering and Technology, 7(1),
2016, pp. 211-219.
http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=7&IType=1
1. INTRODUCTION
Concrete is the most widely used material in the world, with Ordinary Portland
Cement being the current most utilised concrete binder. Although there are variations
in the estimates of the total global concrete production, roughly 3 billion tones of
Portland cement was recorded to have been manufactured during last decade.
This rate of concrete usage is increasing semi-exponentially due to continuous global
industrialization. The current usage is estimated at 4 tones per capita. Concrete’s
environmental impact, especially during the manufacturing process, is ranked as one
of the worst in the world as 1 tone of Portland cement production results in 1 tonne of
CO2 emissions. Portland cement manufacture therefore accounts for 5-8% of global
man-made CO2 emissions.
Pozzolans such as blast furnace slag and fly ash may be activated using alkaline
liquids to form a binder and hence totally replace the use of OPC in concrete. In this
scheme, the alkalinity of the activator can be low to mild or high. In the first case,
with low to medium alkalinity of the activator, the main contents to be activated are
silicon and calcium in the by-product material such as blast furnace slag. The main
binder produced is a C-S-H gel, as the result of a hydration process. In the later case,
the main constituents to be activated with high alkaline solution are mostly the silicon
and the aluminium present in the by-product material such as low calcium (ASTM
Class F) fly ash (Palomo, Grutzeck et al. 1999). The binder produced in this case is
due to polymerization. Davidovits in 1978 named the later as Geo polymers, and
stated that these binders can be produced by a polymeric synthesis of the alkali
activated material from geological origin or by-product materials such as fly ash and
rice husk ash. In the case of geo polymers made from fly ash, the role of calcium in
these systems is very important, because its presence can result in flash setting and
therefore must be carefully controlled. The source material is mixed with an
activating solution that provides the alkalinity (sodium hydroxide or potassium
hydroxide are often used) needed to liberate the Si and Al and possibly with an
additional source of silica (sodium silicate is most commonly used).
1.1. Need of present research
Construction industry requires huge amount of Concrete which in turn consumes
tones of Cement. However the production of Cement causes environmental
degradation in view of huge amount of co2 emissions during the production of
Cement. It is therefore desired that the dominant construction material like Concrete
needs to be manufactured using the least amount of Cement. Research in that
direction has resulted into development of Fly Ash Concrete with partial replacement

3. Comparative Study of Experimental and Analytical Results of Geo Polymer Concrete
http://www.iaeme.com/IJCIET/index.asp 213 editor@iaeme.com
of Cement. But in view of the fact that the demand for Concrete production is rising
in geometric proportion, production of no Cement Concrete, such as Geo Polymer
Concrete is the need of the hour. Several pozzolanic materials can be considered for
producing Geo Polymer Concrete. Fly Ash is one of the pozzolanic material which is
abundantly available. It is a byproduct from thermal power plants and considered to
be marginal material posing disposal issue. Hence Fly Ash based Geo Polymer
Concrete is a construction material of huge potential providing solution to the
environment related issues. Considerable research is being carried out on Fly Ash
based Geo Polymer Concrete. While properties and performance of Geo Polymer
Concrete to a limited extent has been understood, the critical review of the related
literature reveals that very limited published results are available for Geo Polymer
Concrete with higher alkaline liquid ratio above 0.5. Further, very little work seems to
have been carried out on the flexural behavior of Reinforced Geo Polymer Concrete
(RGPC) analytically. Hence, an attempt is made to study the effect of alkaline liquid
ratio of 0.55 and 0.6 with 16 molarity NaOH on mechanical properties and flexural
behavior of Reinforced Geo Polymer Concrete beams both experimentally and
analytically.
2. RESEARCH METHODOLOGY
In this project fly ash is used as the base material for making geo polymer concrete.
NaOH of 16 molarity and alkaline liquid ratios of 0.55 and 0.6 are used in the present
work. Standard specimens were cast to know the mechanical properties of Geo
Polymer Concrete. ANSYS software is used to model the flexural behavior of
Reinforced Geopolymer Concrete Beams. Ultimate load carrying capacity, Maximum
deflection and crack pattern are observed. Reinforced Geo Polymer Concrete Beam
model results will be validated with experimental results.
3. EXPERIMENTAL PROGRAM
3.1. Materials
The materials used for making fly ash-based geo polymer concrete specimens are dry
fly ash as the source material, aggregates, alkaline liquids, water, and super plasticizer
if necessary.
Fly Ash
Chemical analysis of fly ash is shown in Table 3.1 and is within the limits specified
by IS 3812(Part 1)-2003.
Table 3.1 Properties of Fly ash
Characteristics Results /% by mass
Loss on Ignition 1.80
Silica, SiO2 53.36
Alumina, Al2O3 35.93
Iron, Fe2O3 4.36
Magnesium, MgO Nil
Calcium, CaO 4.55

4. D. Annapurna, Prof. Ravande Kishore and M. Usha Sree
http://www.iaeme.com/IJCIET/index.asp 214 editor@iaeme.com
Sodium Hydroxide: Sodium hydroxide solids in the form of flakes with 97% purity
were used in the preparation of alkaline activator.
Sodium Silicate: Sodium silicate in the form of solution was used in the preparation
of alkaline activator.
3.2. Mix Design and concrete production
Design of Geo Polymer mixtures have been carried out by considering coarse
aggregate and fine aggregate together as 75% of total mixture by mass with 30% of it
being fine aggregate. This is similar to the aggregate content required for design of
conventional concrete. Further, assuming design of Geo Polymer Concrete same as
that of conventional concrete and following the guidelines of mix design given by
Rangan [2010], the mixture proportions are arrived at and the same is tabulated at
Table 3.2.
Table 3.2 Mix proportion of different alkaline liquid ratios
Alkaline
liquid ratio
Na2Sio3
(kg/m3
)
NaOH
(kg/m3
)
Water for
NaOH
(kg/m3
)
Fly ash
(kg/m3
)
Fine Agg.
(kg/m3
)
Coarse Agg.
(kg/m3
)
0.55 152.074 27.00 33.829 387.096 540 1260
0.6 160.714 28.54 35.745 375 540 1260
3.3. Mechanical properties
Standard specimens were cast to determine the mechanical properties and the same
are tabulated in Table 3.3.
Table 3.3 Mechanical properties of geo polymer concrete for 0.55 and 0.6 alkaline liquid
ratios
3.4. Reinforced Geo polymer Concrete Beam
Reinforced geo polymer beams were cast with the dimensions of
1500mmx230mmx150mm. All beams were reinforced with 16mm of main
reinforcement at the bottom face with the yield strength of 420 N/mm2.
Testing were
carried out to find out the first crack load and ultimate load at the central deflection
using Universal Testing Machine.
4. ANALYTICAL MODELING USING ANSYS
As stated above, the details of modeling are described in the following text.
4.1. Geometry and Modeling
The Finite Element Analysis included modeling of geo polymer composite reinforced
concrete beams with the dimensions and properties corresponding to beams tested
experimentally in the laboratory. By taking the advantage of the symmetry of the
beam and loading, one quarter of the full beam was used for finite element modeling.
S.No
.
Alkaline
liquid ratio
Compressive
strength (N/mm2
)
Flexural strength
(N/mm2
)
Modulus of Elasticity,
MPa
1 0.55 34 5.16 25000
2 0.6 35.62 5.17 25500

5. Comparative Study of Experimental and Analytical Results of Geo Polymer Concrete
http://www.iaeme.com/IJCIET/index.asp 215 editor@iaeme.com
This approach reduces computational time and Computer disk space requirements
significantly.
4.2. Element Types
Eight noded solid brick elements (Solid 65) were used to model the concrete. This
solid element has eight nodes with three degrees of freedom at each node –
translations in x, y, and z directions. The element is capable of plastic deformation,
cracking in three orthogonal directions, and crushing. Flexural and shear
reinforcements were modeled as discrete reinforcement by using beam188 as shown
in Figure 4.1.
Figure 4.1 Beam model showing solid 65 and beam188 elements
4.3. Real Constants
Real Constant Set 1 is used for the Solid 65 element. Real Constant Sets 2 and 3 are
defined for the beam188 element.
4.4. Material properties
The Solid65 element with reference to ANSYS software requires linear isotropic and
multi-linear isotropic material properties to model concrete. As required for modeling
using ANSYS software the material properties such as compressive strength, Modulus
of Elasticity etc. obtained from the experimental work on mechanical properties of Geo
Polymer Concrete given in Table 3.3 has been used as input data.
4.5. Meshing
To obtain satisfactory results from the Solid 65 element, a rectangular mesh was
considered. Further beam 188 is considered for discretization of reinforcement such
that the concrete and reinforcement share the same node. For concrete and
reinforcement the assigned Mesh attributes are 1, 2.
4.6. Loads and Boundary Condition
Displacement boundary conditions are needed to constraint the model to get a unique
solution.
To ensure that the model acts the same way as the experimental beam boundary
conditions need to be applied at points of symmetry, and where the support exist. The
symmetry boundary conditions were set first. Since this is a simply supported beam so
constraints given at one support is in UX, UY and at the other supports UY is given.
The loads and boundary conditions applied to the model are shown in Figure 4.2

6. D. Annapurna, Prof. Ravande Kishore and M. Usha Sree
http://www.iaeme.com/IJCIET/index.asp 216 editor@iaeme.com
Figure 4.2 Loads and boundary conditions
5. RESULTS AND DISCUSSIONS
The results of Reinforced Geo Polymer Concrete beam obtained both experimentally
and analytically are discussed in the following text.
5.1. Displacement and crack pattern
For the nonlinear analysis, automatic time stepping in the ANSYS program predicts
and controls the load step sizes. The longitudinal displacement at ultimate load is
shown in
Figure 5.1. Final Crack patterns observed in experimental and theoretical studies
are found to have similar pattern, which is depicted in Figure 5.2 and 5.3
Figure 5.1 Longitudinal Displacement vector sum at ultimate load

7. Comparative Study of Experimental and Analytical Results of Geo Polymer Concrete
http://www.iaeme.com/IJCIET/index.asp 217 editor@iaeme.com
Figure 5.2 Final crack pattern at ultimate load
Figure 5.3 Experimental cracks at ultimate load
From Table 5.1 clearly reveal that, at first, second and third cracks, the load
predicted by theoretical model are 15%, 14% and 13% higher than the experimental
values. This implies that the theoretical model overestimating the load for the model
therefore warrants further refinement for estimation of crack loads. However, for
crack at ultimate load the theoretical model underestimates the load marginally by
3%. Hence, for ultimate load condition the model can be carried as reliable and
dependable. Further, at first, second and third cracks, the deflection predicted by
theoretical model are 6, 10 and 14% higher compared to experimental results. Hence
the theoretical model which overestimates the results pertaining to deflection is
acceptable. However for deflection at ultimate load the theoretical model is

8. D. Annapurna, Prof. Ravande Kishore and M. Usha Sree
http://www.iaeme.com/IJCIET/index.asp 218 editor@iaeme.com
underestimating the result marginally by 3%. Hence, this model could be refined or
the theoretical results are to be cautiously considered.
In general the model to predict the results for loads at different crack and
deflection at different stages of loading, there is a scope for improvement in the model
to satisfy all the requirements simultaneously.
Table 5.1 Comparison between Experimental and Theoretical results
Beam
ID
First crack Second crack Third crack Ultimate load
GPC Load
(KN)
Def.
(mm)
Load
(KN)
Def.
(mm)
Load
(KN)
Def.
(mm)
Load
(KN)
Def.
(mm)
Exp. 6.5 0.255 7 0.269 8 0.302 19.5 0.863
Ana. 7.5 0.2700 8 0.2956 9 0.3446 19 0.836
5.2 Load deflection curves of reinforced geo polymer concrete beam
Load deflection curves are plotted using experimental and theoretical results and in
shown in Fig. 5.4. From this figure, it is observed that both curves representing
experimental and theoretical results are very close and at some points overlapping to
each other.
Figure 5.4 Load Deflection curve
6. CONCLUSIONS
 At various stages of cracking except, at the final crack theroretical model
overestimates the loads in the range of 13 to 15%.
 The theoretical model estimates the load at final crack within acceptable limit of -3%.
 At different stages of cracking except at failure the theoretical model overestimates
the deflection in the range of 6 to 14%. Thus enabling the use of theoretical model for
prediction of deflection.
 The predicted and experimental deflection profile match closely, indicating the
dependability of theoretical model.
0
2
4
6
8
10
12
14
16
18
20
0 0.2 0.4 0.6 0.8 1
LoadinKN
Deflection in mm
EXP
ANSYS

9. Comparative Study of Experimental and Analytical Results of Geo Polymer Concrete
http://www.iaeme.com/IJCIET/index.asp 219 editor@iaeme.com
REFERENCES
[1] Rangan,B.V (2010) “Fly-ash based geo polymer concrete” Proceedings of
international workshop on Geo polymer cement and concrete, Allied Publishers
Private Limited, Mumbai, India, December 2010, pp 68-106.
[2] Abdul Aleem M. I, Arumairaj P.D (2012) “geo polymer concrete- a review”,
International Journal of Engineering Sciences & Emerging Technologies, ISSN:
2231 – 6604 Vol.1, Issue 2.
[3] Dattatreya.k, Rajamane.NP (2011) “Flexural behaviour of reinforced geo polymer
concrete beams”, International journal of civil and structural engineering Volume
2, issue 1.
[4] Fareed Ahmed, M., Fadhil Nuruddin, M and Nasir Shafiq (2011) “Compressive
strength and workability characteristics of low calcium fly ash based self
compacting geo polymer concrete”, International Scholarly and Scientific
Research & Innovation volume 5, issue 2.
[5] Kannapiran. K, sujatha. T and nagan. S (2013) “Resistance of reinforced geo
polymer concrete beams to acid and chloride migration”, Asian journal of civil
engineering (BHRC) vol.14, issue 2.
[6] Kumarave. S, Thirugnanasambandam. S (2013) “Flexural Behaviour of Low
Calcium Fly ash Based Geopolymer Concrete Beams,” International Journal of
Structural and Civil Engineering ISSN: 2277-7032 Volume 2 Issue 11.
[7] Madheswaran C. K, Dattatreya J. K, Ambily P.S, Karansingh (2014)
Investigation on behaviour of reinforced geo polymer concrete slab under
repeated low velocity impact loading International Journal of Innovative
Research in Science, Engineering and Technology Vol. 3, Issue 3.
[8] Pateel Alekhya, S. Aravindan (2014) “Experimental investigations on geo
polymer concrete”, International journal of civil engineering and technology
(ijciet) volume 5, issue 4.
[9] Ruby Abraham, Deepa Raj. S, Varghese Abraham (2013) “Strength and
behaviour of geo polymer concrete beams”, International journal of innovative
research in science, engineering and technology, volume 2, special issue 1.
[10] Shaishav R. Viradiya, Tarak P. Vora (2014) “Comparative study of experimental
and analytical results of frp strengthened beams in flexure”, International Journal
of Research in Engineering and Technology (ijret) Volume 03, issue 04.
[11] Sameer Ul Bashir, Effect of Alkali Materials on Geo Polymer Concrete,
International Journal of Civil Engineering and Technology, 6(1), 2015, pp. 01-
13.
[12] Sameer Vyas, Neetu Singh, Rp Pathak, Pankaj Sharma, Nv Mahure and Sl Gupta,
Behaviour of Alkali Activated Fly Ash-Based Geopolymer Concrete on Thermal
Activation, International Journal of Civil Engineering and Technology, 5(4),
2014, pp. 28-36.
[13] Srinivas murthy T.V, Ajeet kumar Rai (2014) “Geo polymer concrete, an earth
friendly concrete, very Promising in the industry”, International journal of civil
engineering and technology (ijciet) volume 5, issue 7.
[14] Uma.k, Anuradha.R, venkatasubramani. R (2012) “Experimental investigation
and analytical modeling of reinforced geo polymer concrete beam”, International
journal of civil and structural engineering volume 2, issue 3.