Study On Compressive Strength Of Fly ash based Geopolymer Concrete

PROJECT MEMBERS:

P. Bhuvaneswari (01709111010)

S. Ramalakshmi (01709111033)

S. Saranyadevi (01709111040)

GUIDED BY

Mr. S. Aravindan., M.E.,

INTRODUCTION:

• The growth of the world is dependent upon infrastructure development. Cement is one of the major construction materials used in infrastructure around the world.

• The emission of carbon-di-oxide during the manufacturing of cement pollutes the atmosphere.

The production of one ton of Portland cement emits one ton of carbon-di-oxide into the atmosphere.

In order to address the environmental effect, there is a need to use Geopolymer concrete.

GEOPOLYMER CONCRETE:

• Geopolymer concrete is a new material that has fly ash instead of cement as a binder.

• Fly ash and Aggregates are activated with alkali solution to produce geopolymer concrete.

ADVANTAGES:

Resistance to fire, alkali aggregate reaction and sulphate attack.

Durable building material.

Aesthetic appearance.

Reducing segregation and bleeding.

Easy to use , recyclable and less expensive

APPLICATIONS:

Civil construction applications

Building materials

Mining

Environment/ Waste management

Special applications

OBJECTIVES:

To develop a mixture proportion to manufacture high Calcium flyash based geopolymer concrete.

To identify and study the effect of parameters that affects the properties of high Calcium flyash based geopolymer concrete.

The parameter includes Molarity, alkaline / fly ash ratio, Sodium hydroxide / Sodium silicate ratio and curing type.

LITERATURE REVIEW:

Davidovits, J. (1994). “Properties of Geopolymer Cements”. First International Conference on Alkaline Cements and Concretes, Kiev, Ukraine, 1994, SRIBM, Kiev State Technical University.

proposed that an alkaline liquid could be used to react with the silicon and the aluminium in a source material of geological origin or in by product materials to produce binders.

Kyoto Protocol (1997). “Geopolymer Composites Layers for Strengthening Concrete Structures”. Geopolymer Materials Vol.99, pp. 81-91.

The trading of carbon dioxide emissions is a critical factor for the industries.

The ‘tradable emissions’ refers to the economic mechanisms that are expected to help the countries worldwide to meet the emission reduction targets.

Roy, D. M.(1999), “Alkali-Activated cements, Opportunities and challenges.” Cement and Research Vol. 24, pp. 22.

One ton of cement-one ton of carbon- di –oxide

De-carbonation of limestone.

Grutzeck, M. W.(1999), “Alkali-Activated Fly Ashes, A Cement for the Future.” Cement and Concrete Research Vol. 29, pp. 1323-1329.

Geopolymers are members of the family of inorganic polymers.

Higher compressive strength-Higher curing temperature and longer curing time.

Barbosa, V. F. F., MacKenzie, K. J. D., C. Thaumaturgo. (2000). “Synthesis and Characterisation of Materials based on Inorganic Polymers of Alumina and Silica: Sodium Polysialate Polymer.”International Journal of Inorganic Materials Vol. 2, pp. 309-317.

Calcined source materials demonstrated a higher final compressive strength.

T.Chareerat, P. Chindaprasirt, V. Sirivivatnanon (2007) “Workability and Strength of coarse high calcium fly ash geopolymer.” Cement and Concrete Composites Vol. 29, pp. 224-229.

To prepare geopolymer from a class C fly ash and a mixed alkali activator.

Alkaline solution ratio 0.67-1.0

Compressive strength was in the range of 10-65MPa.

SA Kristiawan (2011) international seminar on climate change, environmental insight for climate change mitigation, “Investigation on fresh and mechanical properties of class C fly ash based geopolymer mortar, ISBN no 979-978-3456-85-2.

To investigate the fresh properties of high calcium fly ash based geopolymer concrete.

The water to fly ash ratio of 0.3 reached higher compressive strength.

EXPERIMENTAL INVESTIGATION

NaOH(pellets)

Water

NaOH solution

Na2SiO3 solution

Alkaline solution

Mixing for4 minutes

High Calcium Geopolymer concrete

Fly ash

Aggregates

Mix

ing

for3

m

inut

es

Mix

ing

for

3 m

inut

es

Mix

ing

for

3 m

inut

es

Chemical composition of class C fly ash:

Oxides Composition %

Tested Specified (max) as per ASTM

SiO2 26.62 25 - 42

Al2O3 17.78 15 - 21

Fe2O3 8.9 5 - 10

CaO 25.64 17 - 32

MgO 5.5 4 - 12.5

NaO 1.52 0.8 - 6

SO3 4.35 0.4 - 5

LOI 0.6 0.1 - 1

Test data for materials:S.NO GRADE

DESIGNATION

M 20 10 M 12 M 16 M

1 Cement used

Zuari cement OPC 53 grade

- - -

2 Fly ash used

- Class C Class C Class C

3 Specific gravity of cement

3.15 - - -

4 Specific gravity of fly ash

- 2.806 2.806 2.806

5 Specific gravity of water

1.00 1.00 1.00 1.00

6 Specific gravity of 20 mm Aggregate

2.884 2.884 2.884 2.884

7 Specific gravity of sand

2.605 2.605 2.605 2.605

8 Water absorption of 20 mm Aggregate

0.96% 0.96% 0.96% 0.96%

9 Water absorption of sand

1.21% 1.21% 1.21% 1.21%

Total quantity of materials:

S.NO GRADE DESIGNATION M 20 GC

1 Mass of Cement in kg 61.49 -

2 Mass of Water in kg 18.99 21.2

3 Mass of fine aggregate in kg 93.67 125.61

4 Mass of coarse aggregate in kg 187.28 282

5 Water cement ratio 0.5 0.4

EXPERIMENTAL RESULTS

Initial setting time Final setting tiime0

1

2

3

4

5

6

Initial and Final setting time of fly ash

Initial setting timeFinal setting timeH

ours

Workability of fly ash:

10 M 12 M 16 M0

1

2

3

4

5

6

7

8

MolaritySlu

mp

(m

m)

Molarity

Compressive strength for 10 M, 12 M and 16 M

 

7 14 280

2

4

6

8

10

12

14

16

10 M12 M16 M

C

ompr

essi

ve s

tren

gth

(N/m

m²)

Days

Comparison of results:

Authors S.A.kristiawan B.V.Rangan

Water to fly ash ratio

0.2 – 0.3 0.3-0.4 0.4

Curing type oven oven Room temperature

NaOH/Na2siO3 ratio

0.4 0.4 2.5

Molarity 8 M 8 M to 16 M 10 M, 12 M and 16 M

Compressive strength (N/mm²) at 28 days

48 40 - 90 14.44

CONCLUSIONS:

16 M concentration of sodium hydroxide solution results in higher compressive strength of geopolymer concrete than 10 M and 12 M.

Sodium hydroxide to sodium silicate ratio of 2.5

results in better compressive strength of geopolymer concrete.

Longer curing time produces higher compressive strength of geo polymer concrete.

The slump value of the fresh geopolymer concrete increases with the increase of extra water added to the mixture.

As the molarity increases the compressive strength of geo polymer concrete is also increases.

The average density of geopolymer concrete is similar to that of OPC concrete.

The average compressive strength of geopolymer concrete is less than the conventional concrete.

THANK YOU