SSRG International Journal of Civil Engineering (SSRG-IJCE) – EFES April 2015

ISSN: 2348 – 8352 www.internationaljournalssrg.org Page 96

Geopolymer Concrete - A Review Bharat Bhushan Jindal

#1, Kamal Khetarpal

*2

#Assistant Professor, Department of Civil Engg., MM University, Sadopur, Ambala, Haryana, India

*Assistant Professor, Department of Civil Engg., MM University, Sadopur, Ambala, Haryana, India

Abstract- Concrete made up of cement, aggregates, water &

additives is the world’s most consumed construction material

since it is found to be more versatile, durable and reliable.

Concrete is the second most consumed material after water

which required large quantities of Portland cement. The

production of Ordinary Portland Cement (OPC) causes havoc to

the environment due to the emission of CO2 as well mining also

results in unrecoverable loss to nature. Estimated carbon

emissions from cement production in 1994 were 307 MtC, 160

MtC from calcination, and 147 MtC from energy use which

account for 5% of 1994 global anthropogenic CO2 emissions.

Hence, it is the need of hour to find an alternative material to the

existing most expensive cement-concrete. Geopolymer concrete is

an innovative construction material which shall be produced by

the chemical action of inorganic molecules. Fly Ash, a by-

product of coal obtained from the thermal power plant is plenty

available worldwide. Fly ash rich in silica and alumina on

reacting with alkaline solution produce aluminosilicate gel that

act as the binding material for the concrete. It is an excellent

alternative construction material to plain cement concrete

without using any amount of ordinary Portland cement.

Geopolymer concrete shows a greener substitute for ordinary

Portland cement concrete in some applications.

This paper briefly reviews the structural properties of

Geopolymer concrete and its applications.

Keywords— Concrete, Geoploymer, Geoploymer concrete.

I. INTRODUCTION

A. Concrete

Concrete is one of the most widely used

construction material in the world. Ordinary

Portland cement (OPC) is conventionally used as

the primary binder to produce concrete. Production

of Portland cement is currently exceeding 2.6

billion tons per year worldwide and growing at 5

percent annually which generates nearly 7% of

atmospheric carbon-di-oxide contributing largely to

the global warming. Cement manufacturing is

power intensive and about 120 kWh of power is

required to produce one tons of cement resulting

into consumption of nearly 200 kg of coal. On the

other hand, a huge volume of fly ash is generated

around the world. Most of the fly ash is not

effectively used, and a large part of it is disposed in

landfills which affects aquifers and surface bodies

of fresh water. Hence, it is the need of hour to find

an alternative material to the existing most

expensive cement-concrete.

Several studies have been carried out to reduce the

use of Portland cement in concrete to address the

global warming issues. These include the utilization

of supplementary cementing materials such as fly

ash, silica fume, granulated blast furnace slag, rice-

husk ash and metakaolin, and the development of

alternative binders to Portland cement.

B. Geopolymers

Geopolymers are polymers which undergo

polycondensation and set fast at low temperature

within a few minutes. They are hard, inorganic ,

non-inflammable as well as stable at temperature up

to 1250 0C.[ D. Joseph 2002]. Geopolymers better

can be described as a family of mineral binders with

chemical composition similar to zeolites but with an

amorphous microstructure. Geopolymers results in

to polycondensation of silica and alumina from a

source material rich in silica (Si) and aluminium

(Al) like fly ash, silica fume, rice husk ash etc. to

attain structural strength instead of forming the

calcium-silicate-hydrates as in case of ordinary

Portland cement [N.P. Rajamane 2009].

C. Geopolymer Concrete

Geopolymer concrete is a new concrete which does

not utilize any Portland cement as a binder, binding

properties are produced by the reaction of an

alkaline liquid with a source material which is rich

in silica and alumina.

SSRG International Journal of Civil Engineering (SSRG-IJCE) – EFES April 2015

ISSN: 2348 – 8352 www.internationaljournalssrg.org Page 97

The geopolymers are composed of any thermally

activated natural materials like Meta kaolinite or

industrial by-products like fly ash or slag to provide

a source of silicon (Si) and aluminium (Al). These

Silicon and Aluminium is dissolved in an alkaline

activating solution and subsequently polymerizes

into molecular chains and become the binder.

Davidovits (2002) concluded that the production of

one tons of Geopolymer binder generates 0.18 tons

of CO2, from the combustion of carbon-fuel,

compared to one tons of CO2 from Portland cement.

II. GEOPOLYMER CONCRETE MATERIALS

Fly ash, a by-product from thermal power stations

which is found to have rich in silica and alumina is

used in Geopolymer concrete which further helps in

reducing global warming.

GGBS, Ground-granulated blast-furnace slag which

is a by-product of iron and steel-making industry

obtained from a blast furnace and is a fine powder.

GGBS is a glassy, granular, non-metallic material

consisting essentially of silicates and aluminates of

calcium and other bases. GGBS has been widely

used in Europe, United States and in Asia

(particularly in Japan and Singapore) for its

superiority in concrete durability.

Aggregates, fine and coarse aggregates are used in

Geopolymer concrete.

Alkaline Solutions, Sodium or Potassium based

hydroxide and silicate can be used as alkaline used

which on reacting with silica and alumina of fly ash

will result into production of binder material.

III. GEOPOLYMER CONCRETE PROPERTIES

A. Compressive Strength

Compressive strength is one of the most essential

properties of concrete. Anuar et. al, (2011)

explained that the higher concentration of sodium

hydroxide solution inside the Geopolymer concrete

will produce higher compressive strength of ;

because NaOH will make the good bonding

between aggregate and paste of the concrete.

B.Vijya Rangan et. al, (2004) stated that the

compressive strength of Geopolymer concrete is

very high compared to the ordinary Portland cement

concrete. The compressive strength of Geopolymer

concrete is about 1.5 times more than that of the

compressive strength with the ordinary Portland

cement concrete, for the same mix. Similarly the

Geopolymer Concrete showed good workability as

of the ordinary Portland Cement Concrete.

C.K. Madheswaran et. Al. (2013) concluded from

their experimental study that increasing the molar

ratio of NaOH in GPC from 3M to 7M increases the

compressive strength which was higher at 7M

B. Durability

Rangan, B.V. (2008) stated that Geopolymer

concrete is more resistant to heat, sulphate attack,

water ingress & alkali-aggregate reaction. The role

of calcium in Geopolymer concrete made up of fly

ash is very prominent since it may cause flash

setting.

Wallah et. al, (2006) Explained that, heat-cured fly

ash-based Geopolymer concrete undergoes low

creep and very little drying shrinkage in the order of

about 100 micro strains after one year. And it has

an excellent resistance to sulphate attack.

Chanh et al., (2008) stated that fly ash-based

Geopolymer had been proved to provide better

resistance against aggressive environment. As such,

this advantage can be used to construct structure

that exposed to marine environment.

Sathia et al.,(2008) explained that the exposure of

Geopolymer in acid solution shows that the weight

loss due to the exposure is only 0.5% compared to

normal concrete when immersed in 3% sulphuric

acid.

SSRG International Journal of Civil Engineering (SSRG-IJCE) – EFES April 2015

ISSN: 2348 – 8352 www.internationaljournalssrg.org Page 98

IV. ECONOMIC BENEFITS OF GEOPOLYMER

CONCRETE

N A Lloyd and B V Rangan (2010) concluded that

heat-cured, low-calcium fly ash-based Geopolymer

concrete is estimated to be about 10 to 30 percent

cheaper than that of Portland cement concrete. In

addition, the appropriate usage of one ton of fly ash

earns approximately one carbon-credit which in

terms of ecological aspect makes it more

economical.

One tons of low-calcium fly ash can manufacture

approximately three cubic meters of high quality fly

ash-based Geopolymer concrete. Furthermore, the

very little drying shrinkage, the low creep, the

excellent resistance to sulfate attack, and good acid

resistance offered by the heat-cured low-calcium fly

ash-based Geopolymer concrete may yield

additional economic benefits when it is utilized in

infrastructure applications.

Geopolymer concrete has significant advantages

over standard concretes. It is much more durable

than standard concrete and requires little repair,

thus saving huge amounts of money to be spent on

repairing and maintaining concrete based

infrastructure.

V. NECESSITY OF GEOPOLYMER CONCRETE

Owing to the tremendous growth in development of

infrastructure globally, consumption of cement as

per International Cement Review’s report was

3,294 million tons in 2010 which is increasing by

nearly 12% annually resulting which significantly

create a huge shortage on limestone in future, in

addition to this emitting of CO2 in the atmosphere is

the major threat resulting into global warming.

Kumar V. et al. (2005) submitted the estimate in

their report that the thermal power industry is

expected to produce fly ash to about 170 million

tons by 2012 and 225 million tons by 2017.

Lokeshappa et al. (2011) stated that the fly ash

utilization rate in the construction field is 38%,

remaining portions of the fly ash stored in pond and

pollute the environment of the region. So, it

necessitates to undertake research and

development for studying the structural properties

of fly ash and to utilize the industrial waste

products in the construction.

Above study clearly indicate that if Geopolymer

concrete is developed then it will be of greater help

to consume industrial waste materials along with

replacement of Portland cement which will

significantly help in reducing global warming.

VI. APPLICATIONS

Aleem et. al, (2012) mentioned that, Geopolymer

Concrete can be used in the precast industries, so

that huge production is possible in short duration

and the breakage during transportation shall also be

minimized. It shall be effectively used for the beam

column junction of reinforced concrete structures

and infrastructure works. In addition to that the fly

ash shall be effectively used and hence no landfills

are required to dump the fly ash.

Anuar et. al, (2011) in this respect, the Geopolymer

technology proposed by Davidovits shows

considerable promise for application in concrete

industry as an alternative binder to the Portland

cement. It can be used to produce precast railway

sleepers and other pre-stressed concrete building

components.

VII. CHALLENGES

In addition to various advantages expected from

Geopolymer concrete over ordinary Portland

cement based concrete a few of the challenges may

have to overcome before its practical application.

Geopolymer concrete requires the use of chemicals

which can be harmful and if not handled properly.

Durability aspect of geoploymer concrete is still in

the process of investigation which need to be

established before its commercial application.

SSRG International Journal of Civil Engineering (SSRG-IJCE) – EFES April 2015

ISSN: 2348 – 8352 www.internationaljournalssrg.org Page 99

Geopolymer concrete mix design is yet to establish

which is still on the bases on conventional concrete

mix design methods.

VIII. CONCLUSIONS

Fly ash-based Geopolymer is better than normal

concrete in many aspects such as compressive

strength, exposure to aggressive environment,

workability and exposure to high temperature.

Study shows that Geopolymer concrete is more

resistant to corrosion and fire, has high compressive

and tensile strengths, and it gains its full strength

quickly (cures fully faster). It also shrinks less than

standard concrete. Thus, owing to these structural

advantages it may be concluded that in near future

Geopolymer concrete may find an effective

alternate to standard cement concrete.

A detailed research and study is required about

Geopolymer concrete so that researches should

come to a common conclusion considering all the

merits as well demerits.

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