USE OF MARBLE DUST IN CONCRETE

S.P.SANGEETHAHOD CIVIL

DEPARTMNET OF CIVIL ENGINEERING

SUSTAINABLE DEVELOPMENT

• The sustainable development is achieved when the natural as

well as artificial resources are well managed.

• It is meant to decrease the adverse effects which is caused by

the construction industry on the environment.

• Geo polymer concrete is one of the answer for the sustainable

development.

• It reduces the impact of concrete on the environment.

GEOPOLYMERS

• Geo polymer concrete is obtained from the reaction of the

material which is rich in silica and alumina.

• The beauty of geo polymer is that it does not uses cement.

• Normally fly ash is used as a source material which is rich in

silica and alumina.

• Fly ash is known for its properties as an mineral additive in

concrete.

GEOPOLYMERS

There are many other types of geo polymer concrete which are

based on the material used.

Fly ash based geo polymer concrete is also one of them.

Geo polymer concrete is well-suited to manufacture precast

concrete products that can be used in infrastructure

developments.

SIGNIFICANCE OF GPC

Since it does not uses cement it leads to prevent the application

of cement as a binding material in concrete.

Thereby reducing the emission of CO2 during the production of

cement as well as setting.

It is a fact that 755Kg of CO2 is emitted when one tone of

cement is manufactured.

Hence these can be avoided by adopting the geo polymer

concrete

Constituents of GPC

Source materials: By-product materials such as fly ash, silica fume, slag, rice-

husk ash, red mud. Natural minerals such as kaolinite, clays.

Alkaline solutions: The alkaline liquids are from soluble alkali metals that are

usually sodium or potassium based. The most common alkaline liquid used in geo polymerisation

is a combination of sodium hydroxide (NaOH) or potassium hydroxide (KOH) and sodium silicate or potassium silicate.

FLY ASH USED

Low-calcium (ASTM Class F) fly ash is preferred as

a source material than high-calcium (ASTM Class C)

fly ash.

The presence of calcium in high amounts may

interfere with the polymerization process and alter the

microstructure

Marble dust

During the cutting process about 25% the original marble

mass is lost in the form of dust.

Marble dust is settled by sedimentation and then dumped away

which results in environmental pollution.

Marble dust can be used either to produce new products or as

an admixture so that the natural sources are used more

efficiently and the environment is saved from dumpsites of

marble waste.

Marble dust

Composition of marble dust

compounds percentage

SiO2 43.35

Al2O3 5.17

Fe2O3 9.70

MgO 7.68

CaO 34.10

USE OF MARBLE DUST IN THE PRODUCTION OF BRICKS.

It is resulted that the clay particles up to 50% by its weight

can be replaced by marble dust without affecting its

mechanical properties.

Finally the average strength of 20% marble dust replaced

bricks has higher strength than other % of replacements.

USE OF MARBLE DUST AS A FINE AGGREGATE IN CONCRETE

Compressive strength of concrete has been increased with

increasing % of marble dust at all levels of curing.

The unit weight of concrete is increased when marble dust is

used as a substitute for fine aggregate. This is because the dust

is a good filler material.

MIXTURE PROPORTIONS OF GEO POLYMER CONCRETE

Since alkali solutions were used, the mix cannot be

proportionated as similar to ordinary portland cement

concrete.

A separate mix design procedure is handled.

MIX DESIGN PROCEDURE

• In order to design the good mix, the alkaline liquid-to-fly ash ratio by

mass, water-to-geo polymer solids ratio by mass, the wet-mixing time, the

heat-curing temperature, and the heat-curing time are selected as

parameters.

• With regard to alkaline liquid-to-fly ash ratio by mass, values in the range

of 0.30 and 0.45 are recommended.

• The mass of combined aggregates as 75 to 80% of the mass of concrete.

• The total aggregates consists of 30% of fine aggregate. From this the

quantity of fine as well as coarse aggregate can be determined.

MIX DESIGN PROCEDURE

And the remaining % consists of marble dust, alkaline liquid,

water.

Based on the alkaline liquid to marble dust ratio the quantity of

dust and alkalies is calculated.

Also the ratio between two alkaline solutions is maintained as 2.5.

Note that wet-mixing time of 4 minutes, and steam-curing at 60C

for 24 hours after casting are proposed. Increased wet mixing

time increased the compressive strength by 30%

MIX DESIGNDensity of Geo polymer Concrete = 2400 Kg/m3

Total Aggregate (Fine Aggregate + Coarse Aggregate) = 77% of 2400

= 1848 Kg/m3

Fine Aggregate = 30% of Total Aggregate

= 554 Kg/m3

Coarse Aggregate = (1848-554)

= 1294 Kg/m3

Marble dust + Chemical + Water = 23% of 2400

= (2400-1848)

= 552 Kg/m3

 

COMPRESSIVE STRENGTH OF CONCRETE AT LIQUID TO DUST RATIO 0.4

TYPE OF CURING

7 DAY STRENGTH

(KN)

AVERAGE STRENGTH

(KN)

28 DAY STRENGTH

(KN)

AVERAGE STRENGTH

(KN)

Ambient curing

49 48.17 275 266.33

42 227

53 297

Hot curing 415 425.33 604 638.67

457 660

404 652

COMPRESSIVE STRENGTH OF CONCRETE AT LIQUID TO DUST RATIO 0.5

TYPE OF CURING

7 DAY STRENGTH

(KN)

AVERAGE STRENGTH

(KN)

28 DAY STRENGTH

(KN)

AVERAGE STRENGTH

(KN)

Ambient curing

49 48.17 275 266.33

42 227

53 297

Hot curing 415 425.33 604 638.67

457 660

404 652

Compressive strength vs type of curing

Compressive strength vs water to solids ratio

COMPRESSIVE STRENGTH VS WATER TO SOLIDS RATIO

DESCRIPTION

The maximum strength is achieved at the lowest water to solids ratio.

As the water to solids ratio increases the strength goes on decreasing.

This is similar to the fly ash based geo polymer concrete. 

COMPRESSIVE STRENGTH VS CURING TIME

DESCRIPTION

In hot curing the strength increases as the duration

of curing increases.

From the graph it is seen that the increase in

strength is rapid only up to 24 hours of curing time.

Beyond this the increase in strength is insignificant.

 

CONCLUSION

The application of marble dust in geo polymer

concrete results in a little decrease in strength when

compared to fly ash based geo polymer concrete.

The mixing of alkali solutions with marble dust

makes the mixing process tedious.

CONCLUSION

Strength obtained in steam curing is relatively higher than

ambient curing. It proves the practical difficulties in curing

because steam curing process is difficult.

But this also exhibits the same features of fly ash based geo

polymer such as

A. decrease in strength when liquid to dust ratio increases and

B. increase in strength with curing time.

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