STUDY OF BEHAVIOUR OF SELF COMPACTING CONCRETE WITH

PARTIAL REPLACEMENT OF CEMENT BY FLY ASH

Guided by:Mr. H. S. Narashimhan

Presented by:Tharanath Salyan P.Adithya G.S.Shwetha L.P.Savinaya S.

SELF COMPACTING CONCRETE

SELF COMPACTING CONCRETE IS A SPECIAL TYPE OF CONCRETE WHICH

HAVE THE ABILITY TO COMPACT ITSELF ONLY BY MEANS OF ITS OWN WEIGHT

WITHOUT THE REQUIREMENT OF VIBRATION. IT IS ALSO KNOWN AS SELF

CONSOLIDATING CONCRETE OR SELF LEVELING CONCRETE.

LITERATURE REVIEW 1986 - HAJIME OKAMURA – FOUNDER A FUNDAMENTAL STUDY ON THE WORKABILITY

OF CONCRETE BY – OZAWA( 1989), OKAMURA(1993) AND MAEKAWA(1999).

2007 – “PERFORMANCE OF SELF-COMPACTING CONCRETE CONTAINING FLY ASH” BY J.M. KHATIB -UNIVERSITY OF WOLVERHAMPTON, UK.

2011-INTERNATIONAL PAPER ON ”SELF COMPACTING CONCRETE WITH FLY ASH FOR NUCLEAR POWER PLANT STRUCTURES” BY R.PREETHA, C.S.PILLAI AND S.C.CHETHAL.

OBJECTIVE TO DETERMINE THE EFFECT OF FLY ASH AS

PARTIAL SUBSTITUTE OF CEMENT ON THE

PROPERTIES OF SCC IN

1) FRESH STATE (FILLING ABILITY AND PASSING ABILITY)

2) HARDENED STATE

(COMPRESSIVE STRENGTH)

DIFFERENT TEST METHODS OF SCCTest method Properties Unit Range of values

Slump flow by Abrams cone Filling ability mm 650 to 800

T50cm slump flow Filling ability Sec 2 to 5

J- ring Passing ability mm 0 to 10

V- funnel Filling ability Sec 6 to 12

V-funnel at T5 mins Segregation resistance

sec 0 to +3

L- box Passing ability H2 / H1 0,8 to 1,0

U-box Passing ability (H2 - H1 )mm 0 to 30

Fill-box Passing ability % 90 to 100

Orimet Filling ability Sec 0 to 5`

GTM screen stability test Segregation resistance

% 0 to 15

METHODOLOGY

1) MATERIAL TESTING

2) CASTING OF THE SAMPLES

3) TESTING OF SAMPLES

4) COMPARISION OF RESULTS

MATERIALSCEMENT – 43 GRADE OPC.

FLY ASH – AS A PARTIAL SUBSTITE FOR CEMENT.

FINE AGGREGATE – RIVER SAND.

COARSE AGGREGATE – 20mm DOWN SIZE.

ADMIXTURE – “AURAMIX 400” – VISCOSITY

MODIFYING AGENT COLLECTED FROM FOSROC

CHEMICALS PRIVATE LIMITED, BANGALORE.

WATER.

CASTING OF SAMPLES

DETERMINATION OF MIX PROPORTION AND OPTIMUM DOSAGE

OF ADMIXTURE – TRIAL AND ERROR METHOD.

CASTING OF CUBES OF 150mm*150mm*150mm SIZE.

PARTIAL REPLACEMENT OF CEMENT BY 30%,40% AND 50% OF

FLY ASH AND CASTING THE CUBES.

CURING OF CASTED CUBES.

TESTING OF SAMPLES

TESTING OF CEMENT CONCRETE CUBES AFTER 7, 14, 28 AND 56

DAYS OF CURING IN COMPRESSION TESTING MACHINE.

TESTING OF CONCRETE CUBES CONTAINING FLY ASH AS A PARTIAL

SUBSTITUTE TO CEMENT AFTER 7, 14, 28 AND 56 DAYS OF

CURING IN COMPRESSION TESTING MACHINE.

COMPARISON OF RESULTS.

TESTS ON CEMENT AND FLY ASHSl. No.

PHYSICAL PROPERTIES

CEMENT FLY ASH

RESULTS REQUIREMENT AS PER IS 8112-1989

RESULTS REQUIREMENT AS PER IS

3812(PT1)-2000

1. FINENESS 7% <10% 43% 34%

2. SPECIFIC GRAVITY

3.15 3.0 - 3.15 2.31 2.20 – 2.50

3. CONSISTANCY 30% 30%

4. INITIAL SETTING TIME

110min >30min

5. FINAL SETTING TIME

425min <600min

6. SOUNDNESS 1mm <10mm

7. COMPRESSIVE STRENGTH

44.30 MPa

>43 MPa

TESTS ON COARSE AGGREGATESSl. No. PHYSICAL PROPERTIES RESULTS

OBTAINEDREQUIREMENTS AS PER

IS 2386(PT3)-1989

1. SPECIFIC GRAVITY 2.76 2.60 - 2.80

2. FINENESS MODULUS 7.35 6.0 - 8.0

3. SURFACE MOISTURE 0 -

4. WATER ABSORPTION CAPACITY 0.45% < 0.60%

5. BULK DENSITY A) DENSE STATE

B) LOOSE STATE

1522.78 kg/m3

1354.01 kg/m3

6. IMPACT VALUE 27.94% < 45%

7. CRUSHING VALUE 24.81% < 45%

TESTS ON FINE AGGREGATESSl.

No.PHYSICAL PROPERTIES RESULTS

OBTAINEDREQUIREMENTS AS

PER IS 2386(PT3)-1989

1. SPECIFIC GRAVITY 2.67 2.60 - 2.70

2. FINENESS MODULUS 2.72 2.20 -3.20

3. BULKING 36% < 40%

4. SURFACE MOISTURE 1.41% < 2%

5. WATER ABSORPTION CAPACITY 1.43% < 2%

6. BULK DENSITY A) DENSE STATE

B) LOOSE STATE

1564 .97 kg/m3

1396.20 kg/m3

MIX DESIGN SELECTION

SL.NO PROPORTION W/C CEMENT F.A C.A ADMIXTURE

RESULT

1 1:1.75:1.25 0.45 3.50 6.125 4.375 0.80% Bleeding2 1:1.75:1.25 0.40 3.50 6.125 4.375 0.80% Segregation3 1:1.75:1.25 0.41 3.50 6.125 4.375 0.80% Light bleeding4 1:1.75:1.25 0.42 3.50 6.125 4.375 0.80% Bleeding5 1:1.75:1.25 0.43 3.50 6.125 4.375 0.80% Bleeding6 1:1.80:1.20 0.40 3.50 6.300 4.200 0.80% Segregation7 1:1.80:1:20 0.41 3.50 6.300 4.200 0.80% Bleeding8 1:1.75:1.25 0.41 3.50 6.125 4.375 0.90% Segregation9 1:1.75:1.25 0.38 3.50 6.125 4.375 1.00% Segregation

10 1:1.85:1.15 0.41 3.50 6.475 4.025 1.20% No slump flow11 1:1.75:1.25 0.41 3.50 6.125 4.375 0.70% Slump-470mm12 1:1.75:1.25 0.42 3.50 6.125 4.375 0.70% Slump-500mm13 1:1.75:1.25 0.43 3.50 6.125 4.375 0.65% Slump-550mm14 1:1.75:1.25 0.45 3.50 6.125 4.375 0.60% Slump-590mm15 1:1.75:1.25 0.46 3.50 6.125 4.375 0.60% Slump-645mm

MIX PROPORTION RESULT

FINAL MIX PROPORTION

• C:FA:CA = 1:1.75:1.25

• WATER/CEMENT RATIO = 0.46

• ADMIXTURE DOSAGE = 0.6% BY WEIGHT OF TOTAL

CEMENTATIOUS MATERIAL.

MATERIALS USED PER CUBIC METER OF CONCRETE

Admixture used was 0.60% of weight of binder.

Sl.

no.

Mix identification MF0% MF30% MF40% MF50%

Raw materials

1. Cement (kg/m3) 423.91 289.13 242.55 193.88

2. Fly ash (kg/m3) 0 123.91 161.70 193.88

3. Fine aggregate(kg/m3) 1140.09 1181.96 1190.75 1207.24

4. Coarse aggregate(kg/m3) 736.0 705.0 705.0 705.0

5. Water/cement ratio 0.46 0.46 0.47 0.49

6. Water content (kg/m3) 195 190 190 190

7. Water/powder content 0.80 0.85 0.85 0.85

8. % of C.A content by volume 32 30 30 30

MIXSLUMP FLOW

(mm)T50 cm SLUMP

FLOW(sec)

J-RING (mm)

DENSITY (Kg/m3)

MF0% 645 3 8 2425

MF30% 635 4 10 2326

MF40% 630 4 10 2277

MF50% 620 5 11 2207

FRESH CONCRETE PROPERTIES

0% 10% 20% 30% 40% 50% 60%605

610

615

620

625

630

635

640

645

650

0% 10% 20% 30% 40% 50% 60%0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

SLUMP FLOW v/s % REPLACEMENT

T50 SLUMP FLOW v/s % REPLACEMENT

0% 10% 20% 30% 40% 50% 60%0

2

4

6

8

10

12

0% 10% 20% 30% 40% 50% 60%2050

2100

2150

2200

2250

2300

2350

2400

2450

J-RING v/s % REPLACEMENT

DENSITY v/s % REPLACEMENT

DISCUSSION

It is observed from both Slump flow v/s percentage of replacement and T50cm slump flow time v/s percentage of replacement graphs that the filling ability of the SCC decreases with the increase in the percentage of replacement of cement by fly ash. In the same way, from the graph of J-ring test, also it is observed that the passing ability of SCC decreases with the increase in the percentage of replacement of cement by fly ash. This may be due to the fly ash used in our project is less finer than cement, the fineness values are given in Table 3.1 and 3.7. But the values obtained are within the limits specified by EFNARC. Hence cement can be successfully replaced by fly ash in SCC up to 50%.

It is observed from the graph the density of concrete decreases with the increase in the percentage replacement of cement by fly ash. This is because of the lower specific gravity of fly ash i.e., lesser than the specific gravity of cement

HARDENED CONCRETE PROPERTIESSl. no

Cement in Kg/m3

Fly ash W/C ratio

Compressive strength in N/mm2

In % In Kg/m3 7 days 14 days

28 days

56 days

1. 423.91 0 0 0.46 37.06 40.55 49.05 53.69

2. 289.13 30 123.91 0.46 27.47 30.52 38.41 43.60

3. 242.55 40 161.70 0.47 16.57 19.79 25.64 30.46

4. 193.88 50 193.88 0.49 13.95 17.44 23.54 28.74

0% 30% 40% 50%0

10

20

30

40

50

60

7 Days14 Days28 days56 days

COMPRESSIVE STRENGTH V/S % REPLACEMENT

DISCUSSION Here it is observed that as the percentage of Fly ash

increases, compressive strength of the concrete decreases to a certain extent. From the table it has been seen that the strength at 7 days decreases as the percentage of Fly ash is increased. It is further observed that the 7 day strength obtained is almost 65%-75% of 28 days strength of the concrete mix. From the compressive strength test results it is also observed that, there is a marginal increase in strength of 28 days when percentage of Fly ash added is between 30%-50%. From the above graph it can be seen that the compressive strength for individual replacement is increasing from 7 days to 28 days but the compressive strength is decreasing from 0% replacement to 50% replacement

ADVANTAGESEFFECTIVE USE OF FLY ASH.LESS CONSUMPTION OF CEMENT.LESS LABOUR REQUIREMENT.EFFECTIVE IN CONGESTED REINFORCEMENT.NO NEED OF ANY MACHINES FOR VIBRATION.

DISADVANTAGESBRINGING FLY ASH TO THE REQUIRED

LOCATION.MAINTAINING THE PROPORTION AND

DOSAGE OF ADMIXTURE.

THANK YOU!!!