Geopolymer concrete is an innovative, eco-friendly construction material. It is used as replacement of cement concrete. In geopolymer concrete cement is not used as a binding material. Fly ash, silica-fume, or GGBS, along with alkali solution are used as binders.

1. PHYSICAL PROPERTIES AND
APPLICATIONS OF
GEOPOLYMER CONCRETE

2. CONTENTS
• Introduction
• Why not OPC?
• OPC usage without environmental impact
• Why geopolymer concrete?
• Constituents
• Process and Mechanism
• Types of GPC
• Test on GPC
• Properties
• Applications
• Advantages and disadvantages
• Discussion on future development
• Conclusion

3. INTRODUCTION
• Geopolymer concrete is an innovative, eco-friendly
construction material.
• It is used as replacement of cement concrete.
• In geopolymer concrete cement is not used as a binding
material.
• Fly ash, silica-fume, or GGBS, along with alkali solution
are used as binders.
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4. FIGURE 1-GEOPOLYMER CONCRETE
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5. WHY NOT OPC?
• It is the most consumed commodity in the world after
water.
• It is also the most energy intensive material
• Cement production leads to high carbon-dioxide emission.
- 1 ton of CO2 is produced for every 1 ton of cement.
-It is produced by calcination of limestone and burning of
fossil fuels
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6. IS THERE A WAY TO USE OPC WITHOUT
ENVIRONMENTAL IMPACT?
-replacing some limestone with fly ash and blast furnace
slag called as blended cement
-using carbon dioxide emission captures and storage(CCS)
-accelerated carbonation where CO2 penetrate concrete
reacting with Ca(OH)2 in presence of H2O forming CaCO3
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7. WHY GEOPOLYMER CONCRETE?
• Reduces the demand of OPC which leads CO2 emission.
• Utilise waste materials from industries such as fly ash,
silica-fume, GGBS.
• Protect water bodies from contamination due to fly ash
disposal.
• Conserve acres of land that would have been used for coal
combustion products disposal.
• Produce a more durable infrastructure.
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8. CONSTITUENTS
• Coarse aggregate
• Fine aggregate - sand or bottom ash can be used
• Admixture - superplasticizers(naphthalene based or
naphthalene sulphonate based)
• Alkaline activators
-Alkaline activation is a process of mixing powdery
aluminosilicate with an alkaline activator .
-It produce a paste which sets and hardens within short duration
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9. -Alkaline activators commonly used are sodium or potassium
hydroxide.
-They are used in combination with sodium silicate(water
glass) or potassium silicate solution.
-NaOH and Na2SiO3 are more commonly used as it leads to
higher geopolymerisation rate.
-K2SiO3 solution rarely used because of high cost and lack of
easy availability.
-Alkali hydroxide is used for dissolution and sodium-silicate
solution as binder.
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10.  Sodium hydroxide
- dissolved in water to form a semi-solid paste
-higher amount reduces ettringite
-makes crystalline product which is stable in aggressive
environment
 Potassium hydroxide
-improve porosity and compressive strength
 Sodium silicate(water glass)
-available in gel form
-for good pozzolanic reaction it is mixed with NaOH
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11. • Fly ash
-combustion by-product of coal in coal fired power plants
-two classes of fly ash are F and C
TABLE1:CHEMICAL COMPOSITION OF FLY ASH
OXIDES PERCENTAGE
SiO2 52
Al2O3 33.9
Fe2O3 4
CaO 1.2
K2O 0.83
Na2O 0.27
MgO 0.81
SO3 0.28
LOI 6.23
SiO2/Al2O3 1.5 9

12. -fly ash used in concrete to increase life cycle expectancy
-helps in increasing durability
-improves permeability by lowering water-cement ratio
-spherical shape of fly ash improves consolidation of
concrete
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13. • GGBS
-a mineral admixture of silicates and aluminates of Ca and
other bases
- same main chemical constituents as OPC but in different
proportions
- improves compressive strength of GPC
TABLE 2-CHEMICAL COMPOSITION OF GGBS
CEMICAL
CONSTITUTION
CEMENT(%) GGBS(%)
Calcium oxide 65 40
Silicon dioxide 20 35
Aluminium oxide 5 10
Magnesium oxide 2 8
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14. • Silica fume
-also called as micro silica or condensed silica fume
-produced during manufacture of silicon by electric arc
furnace
-another artificial pozzolan
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15. • PROCESS
-Si and Al atoms in source materials dissolved using
alkaline solution.
-Source materials include fly ash ,GGBS, silica-fume.
- gel formed by applying heat.
-This gel binds aggregates and unreacted source material
forming geopolymer concrete
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16. • MECHANISM
-dissolution of Si and Al atoms takes place through the
action of OH ions
-precursor ions condense to form monomers
-polycondensation of monomers to form polymeric
structures
-this framework formed is called as polysilates
-silate stands for silicon-oxo-aluminate building unit
-chains and rings formed and cross linked through
Si-O-Al bridge
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17. TYPES OF GEOPOLYMER
 Slag based geopolymer
-Slag is a mixture of metal oxides and silicon dioxide
- a transparent by-product material formed in the processing
of melting iron ore.
-OPC replacement with slag improve workability and reduce
lifecycle costs
-it also increase its compressive strength
-corex slag, steel slag, iron blast furnace slag are examples
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18.  Rock based geopolymer
-MK-750 in the slag based geopolymer replaced by natural
rock forming minerals forms this geopolymer
-feldspar and quartz are natural rock forming minerals
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19.  Fly ash based geopolymer
- improves workability and increase compressive strength
-reduce cost of OPC along with CO2 emission
-reduce drying shrinkage
-class F fly ash used commonly
Alkali activated geopolymer: Heat curing at 60 to 80 οC
is done. Into 1:2 aluminosilicate gel fly ash particles are
embedded.
Slag based geopolymer:It contains silicate, blast
furnace slag and fly ash
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20.  Ferro-silicate based geopolymer
-same properties as that of rock based geopolymers
-has a red colour
-high iron oxide content
-poly type geopolymer formed by substituting some of the
aluminium atoms in the matrix
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21. TEST ON GPC
• CREEP TEST
-three 150x300 mm cylinders prepared
- placed on creep testing frame with hydraulic loading
system
-before loading 7th day compressive strength determined
-load corresponding to 40% of mean compressive strength
applied
-strain values measured and recorded
-test conducted at 23οC and relative humidity 40-60%
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22. • creep of GPC smaller than that of OPC
• smaller creep due to block polymerisation concept
• presence of micro-aggregates increase creep resisting
function in GPC
• in OPC creep caused by cement paste
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23. • DRYING SHRINKAGE TEST
-75x75x285 mm prisms with gauge studs used
-specimens kept in a controlled temperature environment
-temperature at 23οC and relative humidity 40-60%
-shrinkage strain measurements taken on third day of
casting concrete
-specimen demoulded and 1st measurement taken
-horizontal length comparator used for measurement
-next measurement taken on 4th day
-further measurements taken till one year
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24. • drying shrinkage of GPC is very less
• ambient temperature cured GPC shows more shrinkage
than heat cured GPC
• excess water evaporates during heat curing reducing dry
shrinkage
• drying shrinkage of GPC at ambient temperature is same
as that of OPC
• GPC undergoes shrinkage of 100 micro strains after one
year
• 500-800 micro strains experienced by OPC
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25. FIGURE 2 - DRYING SHRINKAGE OF HEAT CURED AND
AMBIENT CURED SPECIMEN
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26. • COMPRESSIVE STRENGTH
-higher compressive strength when heat activated
-slag addition improves compressive strength at ambient
temperature curing
FIGURE 3- COMPRESSIVE STRENGTH OF GEOPOLYMER CONCRETE
IN AMBIENT CONDITION
Time(days)
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27. • compressive strength of GPC decreased with increasing
fly ash content
• it increased with higher aggregate content
• higher strength at lower alkali content
• compressive strength increased with age
• Polycondensation of silica and alumina contribute to
high strength
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28. • MODULUS OF ELASTICITY AND POISSON’S RATIO
-modulus of elasticity increased with compressive strength
in OPC
-similar trend in GPC but values lower than OPC
-GPC cured at elevated temperature yields higher value of
E than cured at ambient temperature
-Poisson’s ratio of GPC similar to that of OPC and
increased with compressive strength
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29. TABLE 3 -YOUNG’S MODULUS AND POISSON’S RATIO
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30. 28

31. PROPERTIES
• Workability
-increase in NaOH and sodium silicate solution reduce flow
of mortar
-superplasticizer or extra water can be added to increase
workability
• Compressive strength
-it depends on curing time and temperature
-it increase with fly ash content
-it increase with fineness of fly ash
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32. • Resistance against aggressive environment
-used in constructing marine structures
-in OPC white layer of crystals formed on acid exposed
surface
-in GPC there is no gypsum deposition and no visible cracks
-a soft and powdery layer formed during early stages of
exposure which later becomes harder
-mass loss on exposure to H2SO4 in GPC was 3% and in OPC
20-25%
-higher the alkali content higher the weight loss
-GPC showed better resistance
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33. • Behaviour of geopolymer at elevated temperature
-high strength loss during early heating period(up to 200οC)
-beyond 600οC no further strength loss
-no visible cracks up to 600 οC
-minor cracks at 800 οC
-GPC with more compatability between aggregates and matrix
led to less strength loss
• Bond strength
-very high
-about one third of its compressive strength
-four times than that of OPC
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34. APPLICATIONS
• PAVEMENTS
-light pavements can be cast using GPC
-no bleed water rise to the surface
-aliphatic alcohol based spray used to provide protection against
drying
FIGURE 5 – PLACING OF PAVEMENT USING GEOPOLYMER CONCRETE
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35. • RETAINING WALL
-40MPa precast panels were used to build a retaining wall
-panels were 6m long and 2.4m wide
-these panels were cured under ambient condition
FIGURE 6 – PRECASTE GEOPOLYMER RETAINING WALLS FOR A PRIVATE RESIDENCE
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36. • WATER TANKS
-two water tanks were constructed, one with 32MPa concrete with
blended cement and other with GPC
-autogenous healing occurred in OPC due to calcium hydroxide
deposition
-in GPC tank there is little calcium hydroxide
-nominal leaking in tank healed rapidly due to gel swelling
mechanism
FIGURE 7 - INSITU WATER TANKS WITH BLENDED CONCRETE (LEFT)
AND GEOPOLYMER CONCRETE (RIGHT) 34

37. • BOAT RAMP
-approach slab on ground to ramp was made using geopolymer
reinforced with FFRP
-entire constituents remained dormant until activator chemicals were
added
FIGURE8 – BOAT RAMP CONSTRUCTED WITH BOTH IN-SITE AND PRECAST
GEOPOLYMER CONCRETE.
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38. • PRECAST BEAM
-GPC beams formed three suspended floor levels of GCI building
-beams had arched curved soffit
-water pipes were placed inside them for temperature controlled
hydronic heating of building spaces above and below
FIGURE 9 – GEOPOLYMER CONCRETE BEAM CRANED TO
POSITION
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39. ADVANTAGES
 high compressive strength
 high tensile strength
 low creep
 low drying shrinkage
 resistant to heat and cold
 chemically resistant
 highly durable
 fire proof
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40. DISADVANTAGES
 difficult to create
-requires special handling
-chemicals like sodium hydroxide are harmful to humans
-high cost of alkaline solution
 Pre-mix only
-sold only as pre-mix or pre-caste material
 Geopolymerisation process is sensitive
-lacks uniformity
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41. DISCUSSION ON FUTURE DEVELOPMENT
-more studies and wide scale acceptance for using GPC in
precast concrete products
-making GPC more user friendly by using lower amount
of alkaline solution
-producing more cost effective geopolymer
-replacing fine aggregate with quarry sand as demand for
natural sand is increasing
-studies on fibre reinforced geopolymer concrete for
improving flexural strength
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42. CONCLUSION
• Geopolymer concrete is a promising construction
material due to its low carbon dioxide emission
• High early strength, low creep and shrinkage, acid
resistance, fire resistance makes it better in usage than
OPC
• Wide spread applications in precast industries due to
-its high production in short duration
-less breakage during transportation
• Enhanced research along with acceptance required to
make it great advantage to the industry
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43. REFERENCES
• Aslani (2015); Thermal Performance Modelling of Geopolymer
Concrete, Journal of Materials in Civil Engineering
• Shankar H Sanni (2012); Performance of Geopolymer Concrete
under severe environmental conditions, International Journal on
Civil and Structural Engineering
• Ramujee et al (2014), Development of Low Calcium Fly
Ash Based Geopolymer Concrete, IACSIT International Journal
of Engineering and Technology, Volume 6
• Lloyd et al (2010);Geopolymer concrete: A review of
development and opportunities
• Bakharev, T., (2005(a)), Resistance of geopolymer materials to
acid attack, Cement and Concrete Research, 35, pp 658-670.
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