The term “geopolymer” was first used by J.Davidovits in the

late 1970s.

Geopolymers have three dimensional amorphous structure

and can be synthesized from by products such as fly ash,

blast furnance slag or geological materials such as metakaolin.

However, metakaolin is expensive and is not used widely in

the construction industry.

Xray fluorescence (XRF)

X-ray diffraction (XRD)

Scanning electron micrograph (SEM)

Fourier transform infrared spectroscopy (FTIR)

Differential scanning calorimetry (DSC)

Thermal gravimetric analysis (TGA)

The chemical composition of the alumino silicate was

determined using XRF shows the chemical

composition of fly ash.

The basic material of the geopolymer based fly ash is

of a prevailingly amorphous character only seldom

containing needle-shaped minority crystals. The X-

ray diffraction (XRD) pattern of fly ash in its as received condition is shown in Fig.

SEM image showing the characteristic morphology of the

original fly ash. The majority of the fly ash particles are

spherical in nature and are precipitator type fly ash.

This ash consists of a series of spherical particles of different

sizes (diameters ranging from 200 to 10 Am). Although

usually hollow, some of these spheres may contain other

particles of a smaller size in their interiors.

The FTIR spectra for both raw fly ash and geopolymer paste demonstrated remarkable differences. The vibration at 1020 cm-1

corresponding to SiO and AlO in the raw fly ash was shifted to less than 1000 cm-1.

DSC was used to measure a number of characteristic

properties of the geopolymer pastes.

Using this technique, it is possible to observe exothermic and

endothermic events as well as glass transition temperatures(Tg).

The range of investigation is between -30 and 100̊ C

Wide range of temperatures. Programmed heating/cooling rates Sensitivity Any material may be tested

Fiber Powder liquid etc;

Small amount of material is needed Does not take much timeClearness of results

Cannot really control the rate of experiment.

Dependent on too many parameters.

Very sensitive to any changes.

The result depends a lot from the operator.

The procedure of standard parameters.

Evaluation is not described.

In this TGA test, the mass loss was measured while the

specimens were gradually exposed to increasing temperatures.

Powdered specimens were used in TGA to ensure the

achievement of thermal equilibrium during transient heating.

Accurate

Low detection limit(up to 10-7 g)

Reliable data

Easy to use

Rather cheap

Disadvantages

Destructive

Limited range of samples

Time consuming

Usually not qualitative

Class C Fly Ash:

For class c fly ash-based

geopolymer paste, low W/F

could meet the demand for an

approving fluidity.

Class C fly ash-based

geoolymer pase and mortar

could both abtain high

compressive strength after

curing a 70 ͦC for 24h.

Compressive strengthof mortar

was much higher than paste

with same water to fly ash

ratio.

Class F fly ash:

Class F fly ash mixed

with calcium hydroxide

geopolymer mortar.

The compressive

strength and the flexural

strength of geopolymer

mortar after being

demolded cured at

standard temperature for

1 day were up to 6.48

MPa and 2.07 MPa.

Geopolymer are new materials which have various application

fields.

Geopolymer concrete showed reduction deterioration in its

properties when exposed to temperatures above 200 ͦC.

Geopolymers shows significant potential to be a material for

the future,because it is not only environmentally friendly but

also possesses excellent mechanical properties.

And it also has a great potential for applications in various

industries.

Thank you