mayur - pozzocrete presentation

World of Processsed Fly ash and its Importance in Concrete

By Mayur PathakG.M. - Product Technology

An AMBUJA Cements Ltd company.

An AMBUJA Cements Ltd company

What is fly ash?

typically spherical, diameter ranging from less than 1µm up to 150 µm.Fly ash is a by-product of the combustion of pulverized coal

in thermal power plants.

The dust collection system (electro static precipitators) removes the fly ash as a fine particulate residue, from the combustion gases.

Fly ash particles are typically spherical, diameter ranging from less than 1µm up to 150 µm.


The Pozzolana Fly ash exhibits pozzolanic activities. A

pozzolana is defined as “a silicious or aluminous material which itself possesses little or no cementitious value but which will, in a finely divided form and in the presence of moisture, chemically react with Calcium hydroxide, at ordinary temperature to form compounds possessing cementitious properties.


Chemical Benefits 1. It contains reactive silica. 2. It reduces heat of hydration. 3. It forms secondary CSH Gel. 4. It improves delayed strength. 5. It protects concrete from salt and

sulphate attacks. 6. It makes concrete impermeable.


Fineness : Scanning electron microscope (SEM) and particle size analysis have shown that particles are spherical and rounded.The size of particles varied from 1 µm to 150 µm. Typically, the size less than 10 µm contributes to the pozzolanic activities. The size above 45 µm hardly contributes to pozzolanic activities. In the power station the raw fly ash is found which varies drastically from 1% retention on 45 micron sieve in the last row to 92% retention on the same sieve.Specific gravity of fly ash varies widely but it is taken as 2.15-2.35.


• Bogues Compounds

C3S = Tricalcium Silicate• C2S = Dicalcium Silicate

C3A = Tricalcium Aluminate C4AF = Tetracalcium Alumino Ferrite

Boring Concrete Chemistry



Ca(OH)2 + SiO2(fly ash) + H --->C3S2H3 C-S-H gel

Tri-calcium silicate 2(3CaO.SiO2)+6H2O- 3CaO.2SiO2.SiO2.3H2O+3Ca(OH)2

In short 2C3S+6H - C3S2H3 + 3Ca(OH)2Corresponding molecular weights involved are 100 + 24 -- 75 + 49

Di-calcium silicate2(2CaO.SiO2) +4H20- 3CaO.2SiO2.3H2O + Ca(OH)2In short 2C2S + 4H -- C3S2H3 + Ca(OH)2

Corresponding molecular weights involved are 100 + 21 -- 99 + 22

1 . Fly ash particles are perfectly spherical in shape.

2 . Particles size smaller than cement.3. Fly ash reduces water demand due to

ball bearing effect.4. Fly ash makes mix cohesive and

facilitates pumping.5. Fly ash helps in slump retention.

Physical BenefitsPhysical Benefits


SEM Pictures


Necessity of processed fly ash

1 2 3 4 5 6 7 8 9 100

10

20

30

40

50

60

2022

34

55

38

20

28

45

2219

Run Off Station Ash Quality

ROS 45

Week No

ROS% 45

MICRON


Standard Pozzocrete Comparision

Test

Min/Max ASTM C-618 EN-450 BS-3892 IS-3812 P30 P40 P60 P63 P100 Category Sr No Unit Max S N

1 Fineness-Specific surface by m2/kg MinNot specified

320 Not 280 320 400 600 Blaines Air- Permeability specified

2 ROS 45 Micron % Max 34.0 12.0 40.0 12.0 34.0 34.0 25.0 18.0 10.0 0

3 Loss On Ignition % Max 6.0 7.0 7.0 5.0 3.0 2.5 2.5 2.5 2.5

5Water Requirement(Max of control) % Max 105.0 95.0 not specified 95.0 not speci 105.0 100.0 96.0 95.0 95.0

6 Moisture Content % Max 3.0 Not Specified 0.5 2.0 0.5 0.5 0.5 0.5 0.57 Soundness By Autoclave Max 0.8% 10mm 0.8% 0.2% 0.2% 0.1% 0.1% 0.1%

8Compressive strength at 28 Days % % Min 75.0 75.0 80.0 80.0 75.0 80.0 85.0 90.0 95.0

of plain cement mortar, 9 Lime Reactivity N/mm2 Min Not specified 4.5 Not Speci 4.5 5.0 5.5 7.0

Chemical analysis 1 Sio2+Al2O3+Fe2O3 % Min 70.0 70.0 Not 70.0 90.0 90.0 90.0 90.0 90.02 SiO2 % Min Not specified Not Specified Specified 35.0 50.0 50.0 50.0 50.0 50.03 Reactive Silica % Min 25.0 20.0 20.0 20.0 20.0 20.0 20.04 Cao % Max 10.0 10.0 not speci 5.0 5.0 5.0 5.0 5.05 Mgo % Max Not specified 4.0 4.0 4.0 4.0 4.0 4.0 4.06 SO3 % Max 4.0 3.0 2.0 3.0 2.0 2.0 2.0 2.0 2.07 Na2O % Max Not specified 5.0 Not speci 1.5 1.5 1.5 1.5 1.5 1.58 Total Chlorides % Max Not specified 0.1 0.1 0.05 0.05 0.05 0.05 0.05 0.05

Product Confirming to Standards ASTM-C618 ASTM-C618 ASTM-C618 ASTM-C618 ASTM-C-618

EN450-Ncat EN450-Ncat EN450-N cat EN450-N cat EN450-N cat

IS-3812 Part-

1IS-3812 Part-

1IS-3812 Part-

1

EN450-S cat EN450-S cat


Water Requirement of Various Grades of Pozzocrete

P10 P20 P30 OPC P40 P60 P63 P83 P1000

20

40

60

80

100

120 108 104.8 102 100 99.2 96 94 91.2 88

%compared with OPC Linear (%compared with OPC)Various Grades of Pozzocrete

Wat

er r

equi

rem

ent %


Strength factors of Various Grades of Pozzocrete %

0

20

40

60

80

100

120

6472 78

90 94 99 100 105 108

P10P20P30P40P60P63OPCP83P100Linear (P100)

Product Series


Pozzocrete for ConcreteI. Pozzocrete 10- As a filler material and partial

sand replacement.II. Pozzocrete 30 and 40 – widely used for mass

concrete for partial cement replacement up to 70%.

III. Pozzocrete 60 and 63- concrete Ranging from M15 to M45.Partial cement replacement.(fineness 320 m2/kg to400 m2/kg).

IV. Pozzocrete 100- For High performance concrete M50 and above up to M100.(Replacement of Micro silica)


Regular Cement Replacement Application

I. 1.For R.C.C. structures 15% to 35% IS 1489 & IS 456.

II. For Mass concrete structures ,cement replacement can be up to 70-75%.

III. For brick work and plaster.30-40%.IV. For flooring and dado.30-40%.


Particulars Control mix Pozzocrete 60 mix

OPC 400 300

Pozzocrete 60 0 140

Water 160 158

Admixture dosage 1.2% 1.2%

w/c 0.4 0.36

Slump

Initial 150 180

30 min 120 140

60 min 80 120

90 min 100

3 days in Mpa 28 26

7 days in Mpa 35 34

28days in Mpa 44 46

Comparative Trials with Pozzocrete 60 as 32% cement replacement


Fly ash as a Substitute for Microsilica

Superfine fly ash – Pozzocrete 100

ROS on 45 microns – zeroROS on 25 microns – 0.25, maxSSA by Blaine – 625 m2/kg, min


Pozzocrete 100 – Particle Size Distribution


Particulars Control mix Pozzocrete 100 mix

OPC 440 kg 445 kgMicrosilica 45 kg 0Pozzocrete 100 0 50Pozzocrete 60 120 kg 110Water 169 lit 136 litAdmixture dosage 1% 1%w/c 0.28 0.24Initial Slump collapse collapse180 min 200 mm 200 mm1 day in Mpa 25.23 24.443 days in Mpa 55.25 64.77 days in Mpa 65.55 71.1928days in Mpa 96.44 94.89RCPT (28d) in

coloumbs950 1000

Comparative Trials with P100


Material Quantity Rate Amount

OPC 440 6 2640

Micro silica 45 26 1170

P100 0 0 0

P60 120 3.0 360

Total 4170

Quantity P100 Rate P100

OPC 445 6.0 2670

Micro silica 0 26 0

P100 50 10 500

P60 110 3.0 330

Total 3500

P100 Mix Cost Comparison of Binder

• Approximate Cost Saving – 16%


Fly ash as Sand Replacement

Different type of fly ash – coarse Fly Ash (P10) .

P10 specificationsIn the range of 65% to 90% ROS on 45

micronsLOI – Maximum 2.5%


Modifications in Mix Design Using P10• P10 is 100% passing through 600 micron sieve.• Reduction of total fines in a mix from 5 to 15% .• Replace 10 to 20% sand by P10• Total binder content may be reduced around 5% to

10%.• OPC Fly ash proportion should be kept same.• The water demand is reduced by 3 to 5%.


Parallel Trials Conducted for M25

Material (M3)Control mix Sand replacement mixQuantity (kg) Quantity (kg)

OPC 53 UT 263 263

Fly ash 87 87

Water 165 165

20mm 697 818

10mm 231 273

N.S 741 786

C.S 231 0

P10 0 139

Admixture 3.5 3.5


Workability Comparison Control mix P10 mix

Slump readings mm mm

Initial 120 180

30min 100 150

60min 130

90min 120

120min 100

150min


Compressive Strength

Designation 7 Days Mpa 28 Days w/c Sand

replacement by P10 33.5 48.5 0.47

Control mix 28.09 40.27 0.47


Conclusions• Use of P10 as a partial sand replacement gives flexibility to use coarse

sand in mix of any grade.• It reduces segregation problems and makes mix cohesive and hence

pumpable mix for even lower grades of concrete.• It reduces water cement ratio and increases retention time, acts as

mineral admixture.• It reduces fine aggregate content and increases coarse aggregate

content.• The reduction of water cement ratio and increase of CA content results

in increased strength and hence reduced cement content. • Due to reduced water cement ratio and increase CA content we get

increased strength and hence reduced cement content.

.


Some Prestigious Projects with PozzocreteAn AMBUJA Cements Ltd company


Dijibouiti Kempinski hotel

Kuwait Boubyan Sea Port Project

Burj Khalifa Kuwait Al-Hamara Tower


Dij

Ghatghar Dam


DIRK India produces a range of POZZOCRETE grades by mechanical air classification of raw Pulverized Fuel Ash

DIRK India Nashik facility

Product range:POZZOCRETE 40POZZOCRETE 60POZZOCRETE 63POZZOCRETE 10

POZZOCRETE 100

Pozzocrete - A Boon To Construction Industry

•Client•Consultant•Contractor•& Most Importantly ……….

It offers innumerable benefits to various

parties like:-


The Mother EarthEvery ton of cement produced has CO2

Emissions of 0.8to 1 Tons so every Ton of

Pozzocrete replacing cement prevents equal

amount of CO2 emissions in atmosphere.


To summarize: Mr.Adam Neville says that “ importance of fly ash cannot be exaggerated : It is no longer a cheap substitute for cement, nor an “extender” or an addition to the mix. Fly ash bestows important advantages upon Concrete, and it is, therefore, essential to understand the role and influence of fly ash”.


No Fly ash no ConcreteTo end up, let us repeat what E.A.Abdun-

Nur said about the fly ash“In the real world of modern

concrete, fly ash is as essential an ingredient of the mixture as are Portland Cement, aggregate , water and chemical admixtures. In most concretes, I use it in larger amounts (by volume) than Portland Cement , and therefore it is not an admixture. Concrete without fly ash and chemical admixtures should only be found in museum showcases.


mayur - pozzocrete presentation

Documents