Y.Sai compressive strength Faseyemi Victor Ajileye concluded cement

Y.Sai kiran Reddy1, Graduate student – Civil Engineering Department,
saveetha school of engineering ,Saveetha university, Chennai, India,    [email protected]

Likhith krishna2, Graduate student – Civil Engineering Department,
saveetha school of engineering ,Saveetha university, Chennai, India,    [email protected]

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Vinayak dave3, Asst Professor  – Civil Engineering Department, Saveetha
School of Engineering, Saveetha University, Chennai, India,  [email protected]

 

ABSTRACT:

The
use of silica fume had major impact on construction industry. This study is an
experiment on the nature of silica fume and its influences on the properties of
fresh concrete. The partially replacement of cement by silica fume the strength
parameters of concrete have been studied. First, the strength parameters of
concrete without any partial replacement was studied. Then, we replaced the
cement with silica fume of different ratios (10%,15%,20%) and results were
compared with normal concrete .After 10% replacement it is observed that the
strength is gradually decreased .

KEY WORDS: silicafume , Compressive strength  etc

1. INTRODUCTION:

1.1. MATERIALS:

CEMENT  :
ordinary Portland cement (opc) of M53 grade is used in casting

AGGREGATE: coarse aggregate which are sieved  at a size of 20mm are used

WATER: Tap water which are suitable for construction
is used.

SILICAMESH 800:It is used for replacement of cement
by 10%,15%,20%

 water cement
ratio is 0.45

1.2.1.
METHODOLOGY

               

 

FIGURE NO :01

 

 

 

2.
REVIEW OF LITERATURE:

Abdulaziz A. Bubshait
et. al :

Investigated
that the advantages of using micro silica can be considerable as it reduces
thermal cracking caused by the heat of cement hydration and can improve
durability to attack by sulphate and acidic water, giving increase in
performance of concrete. The optimum replacement of cement by silica fume gave
high durability, permeability, high compressive strength

Faseyemi Victor Ajileye

concluded
cement replacement up to 10% with silica fume leads to increase in compressive
strength for M30 grade of concrete. From 15% there is a decrease in compressive
strength for 3, 7, 14 and 28 days curing period. It was observed that the
compressive strength of M30 grade of concrete was increased from 16.15% to
29.24% and decrease from 23.98% to 20.22% maximum replacement level of silica
fume was 10% for M30 grade of concrete.

N.K. Amudhavalli and
jeena Mathew :

This
research concluded that with increase in fineness of cement consistency
increases. Silica fume is having greater fineness than cement and greater
surface area so the consistency increases greatly, when silica fume percentage
increases. The normal consistency increases about 40% when silica fume
percentage increases. The normal consistency increases about 40% when silica
fume percentage increases from 0% to 20%. The 7 and 28 days compressive
strength and flexural strength was obtained in the range of 10% to 15% silica
fume replacement level. Increase in split tensile strength beyond 10% silica
fume replacement was almost unsatisfactory whereas increase in flexural tensile
strength occurred up to 15% replacement. Silica fume to have a more
satisfactory effect on the flexural strength as compared to tensile strength.
When the mix was compared to another mix the weight loss and compressive
strength percentage was found to be reduced by 2.23 and 7.69 respectively when
cement was replaced by 10% of silica fume.

Des King:

Investigated
the impact of silica fume in concrete under various properties such as
workability, permeability, durability, bleeding, heat of hydration, sensitivity
to curing, acid resistance, tensile strength, flexural strength etc. He
concluded that the 28th days strength of concrete with silica fume gives a
higher strength of compressive strength as compared to any other material such
as fly ash , GGBS etc. With addition of silica fume early high compressive
strength can be achieved, further a very high strength can be achieved after 28
days with proper concrete mix design method.

 

Vikas Srivastava et. Al:

Worked
out the workability of concrete on optimum replacement of silica fume by
cement. Their research concluded that the workability reduces with the addition
of silica fume. However in some cases improved workability was observed. With
the addition and variation of replacement levels of silica fume the compressive
strength significantly increased by (6-57%). There was no change observed in
the tensile and flexural strength of the concrete as compared to the
conventional concrete.

Debabrata Pradhan and
D. Dutta :

Investigated
the effects of silica fume on conventional concrete, concluded the optimum
compressive strength was obtained at 20% cement replacement by silica fume at
24 hours, 7days and 28 days. Higher compressive strength resembles that the
concrete incorporated with silica fume was high strength concrete.

3. EXPERIMENTAL
PROCEDURE:

PREPARATION
OF CUBE SPECIMENS:

The
proportion and material for making these test specimens are from the same
concrete used in the field.

SPECIMEN :

3
cubes of 15 cm*15cm*15cm size we need to apply
oil or grease for the cube and tighten the screws of cube as shown in figure 02

         

                                FIGURE NO :02

3.1.MIXING:  After the sample has been mixed, immediately
fill the cube moulds and compact the concrete, either by hand or by vibration.
Any air trapped in the concrete will reduce the strength of the cube.

3.2HAND MIXING:

Mix
the cement on a water tight none-absorbent platform until the mixture is
thoroughly blended and is of uniform colour.                                  

               FIGURE NO :03

Add
the coarse aggregate and mix with cement and fine aggregate until the coarse
aggregate is uniformly distributed throughout the batch.

Add
water and mix it until the concrete appears to be homogeneous and of the
desired consistency.

3.3. CASTING:

The
cubes must be fully compacted moulds should be filled in three approximately
equal layers (50 mm deep). A compacting bar is provided for compacting the
concrete. It is a 380 mm long steel bar, weighs 1.8 kg and has a 25 mm square
end for ramming. During the compaction of each layer with the compacting bar,
the strokes should be distributed in a uniform manner over the surface of the
concrete and each layer should be compacted to its full depth. During the
compaction of the first layer, the compacting bar should not forcibly strike
the bottom of the mould. For subsequent layers, the compacting bar should pass
into the layer immediately below. The minimum number of strokes per layer
required to produce full compaction will depend upon the workability of the
concrete, but at least 35 strokes will be necessary except in the case of very
high workability concrete. After the top layer has been compacted, a trowel
should be used to finish off the surface level with the top of the mould, and
the outside of the mould should be wiped clean.

3.4. DEMOULDING
:

Test
cubes should be demoulded between 16 and 24 hours after they have been made. If
after this period of time the concrete has not achieved sufficient strength to
enable demoulding without damaging the cube then the demoulding should be
delayed for a further 24 hours. When removing the concrete cube from the mould,
take the mould apart completely. Take care not to damage the cube because, if
any cracking is caused, the compressive strength may be reduced.

After
demoulding, each cube should be marked with a legible identification on the top
or bottom using a waterproof crayon or ink. The mould must be thoroughly
cleaned after demoulding the cube. Ensure that grease or dirt does not collect
between the faces of the flanges, otherwise the two halves will not fit
together properly and there will be leakage through the joint and an
irregularly shaped cube may result.

3.5. CURING:

Cubes
must be cured before they are tested. Unless required for test at 24 hours, the
cube should be placed immediately after demoulding in the curing tank or mist
room. The curing temperature of the water in the curing tank should be
maintained at 27-30°C. If curing is in a mist room, the relative humidity should
be maintained at no less than 95%. Curing should be continued as long as
possible up to the time of testing.

In
order to provide adequate circulation of water, adequate space should be
provided between the cubes, and between the cubes and the side of the curing
tank. If curing is in a mist room, there should be sufficient space between
cubes to ensure that all surfaces of the cubes are moist at all times

4. RESULTS
AND DISCUSSION:

The tests conducted on concrete
mix are as follows

4.1.NORMAL
CONSISTENCY TEST:

Time

Penetration
Reading

0

0

5

0

10

0

15

0

20

0

25

3

30

6

4.2.INITIAL SETTING TIME
TEST

Quantity Of Cement Taken (Grams)

Percentage Of Water

Amount Of Water
(Ml)

Penetration Reading

400

25%
 

100
 

31
 

400

30%
 

120
 

23
 

400

35%
 

140
 

15
 

400

36%
 
 

152

7

4.3. FINAL SETTING TIME
TEST

NAME
OF THE TEST

RESULT

Final Setting
Time
 

600minutes(10
Hours)

4.4.COMPRESSIVE
STRENGTH
TEST OF CONVENTIONAL PERVIOUS CONCRETE 
(7,14,28 DAYS)

specimen

compressive strength(7days)

compressive strength(14days)

compressive strength(28days)

CUBE
1

17

23

27.02

CUBE
2

15.8

22

24.04

CUBE
3

17.2

22.5

25.33

4.5.  COMPRESSIVE STRENGTH TEST OF 10% SILICAMESH800
 OF (7,14,28 DAYS):

specimen

compressive strength(7days)

compressive strength(14days)

compressive
strength(28days)

CUBE
1

8.40

36

42.55

CUBE
2

8.4

37.24

43.24

CUBE
3

8.4

37.86

44.66

4.6. COMPRESSIVE STRENGTH
TEST OF 15% SILICAMESH800 CONCRETE OF (7,14,28 DAYS)

specimen

compressive strength(7days)

compressive strength(14days)

compressive
strength(28days)

CUBE
1

27.46

30.04

33.24

CUBE
2

22.57

29.46

34.22

CUBE
3

24.04

32.44

36.08

4.7.
COMPRESSIVE STRENGTH TEST OF 20% SILICAMESH800 CONCRETE OF (7,14,28 DAYS)

specimen

compressive
strength(7days)

compressive
strength(14days)

compressive strength(28days)

CUBE 1

26.53

25.2

31.28

CUBE 2

22.44

26.04

30.04

CUBE 3

22.02

27.46

29.77

4.8.COMPARISION OF COMPRESSIVE STRENGTH
FOR DIFFERENT PERCENTAGES OF SILICAMESH800 :

                        Figure no:4                                                                   

5.  CONCLUSION

·    
That with
increase in workability the compressive strength decreases.

·    
The optimum
replacement of cement with silica fume 10% to 15% leads to increase in
compressive strength whereas the percentage replacement of 20% leads to
decrease in compressive strength.

·    
Variation
of w/c ratio has an impact on compressive strength of concrete. With the
increase in w/c ratio the compressive strength decreases and vice versa.

·    
Addition of
silica fume in proper proportion improves durability attack by acidic waters
and improving concrete conditions.

·    
Silica fume
having high fineness leads to high normal consistency.

·    
Silica fume
gives a higher strength of compressive strength as compared to any other
material such as fly ash, GGBS.

 

6.
REFERENCES:

1 Abdulaziz A. Bubshait, Bassam M. Tahir & M. O. Jannadi,
“Use of Microsilica in Concrete Construction”, Article 1996

2 Faseyemi Victor Ajileye “Investigations on Microsilica (Silica
Fume) As Partial Cement Replacement in Concrete” Global Journal of Researches
in Engineering Civil and Structural engineering Volume 12 Issue 1 Version 1.0
January 2012. Online ISSN: 2249-4596 & Print ISSN: 0975-5861. PP. 17-23.

 

3 N. K. Amudhavalli, Jeena Mathew “Effect of Silica Fume on
Strength and Durability Parameters of Concrete” International Journal of
Engineering Sciences & emerging Technologies, August 2012, Volume 3, Issue
1, pp: 28-35.

 

4 Des King “The Effect of Silica Fume on the Properties of
Concrete as defined in Concrete Society Report 74, Cementitious materials” 37th
conference on our world and structures 29-31 August 2012, Singapore. Article
online ID-10037011.

5 Vikas Srivastava, V.C. Agarwal and Rakesh Kumar “Effect of
Silica Fume on Mechanical Properties of Concrete” Vol. 1(4) September 2012, J.
Acad. Indus Res. Vol. 1(4) September 2012 176, ISSN:2278-5213

6 Debabrata Pradhan, D. Dutta ” Effects of Silica Fume in
Conventional Concrete” Debabrata Pradhan et Al International Journal of
Engineering Research and Applications. ISSN:2248-9622, Vol. 3, Issue 5, Sep-Oct
2013

 

7 Alaa M. Rashad, Hosam El-Din H. Seleem, and Amr F. Shaheen
“Effect of Silica Fume and Slag on Compressive Strength and Abrasion Resistance
of HVFA Concrete” Vol.8, No.1, pp.69–81, March 2014 DOI 10.
1007/s40069-013-0051-2, ISSN 1976-0485 / eISSN 2234-1315.

 

8 Prof. Vishal S. Ghutke, Prof. Pranita S.Bhandari “Influence of
Silica Fume on Concrete”. 2014. IOSR Journal of Mechanical and Civil
Engineering (IOSR-JMCE), e-ISSN: 2278-1684, p-ISSN:2320-334X, PP 44-47.

 

9 IS 10262:2009, “Guidelines for Concrete Mix Design”. Bureau of
Indian Standards, New Delhi, India.

 

10 IS 456:2000, “Plain and Reinforced Concrete-Code of
Practice”. Bureau of Indian Standards, New Delhi, India.

 

11 IS 383:1970,”Specification of Coarse and Fine Aggregate from
Natural Sources for Concrete”. Bureau of Indian Standards, New Delhi, India 

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