EFFECT OF FLY ASH ON COMPRESSIVE STRENGTH AND …€¦ · EFFECT OF FLY ASH ON COMPRESSIVE STRENGTH...
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EFFECT OF FLY ASH ON COMPRESSIVE STRENGTH AND WORKABILITY OF CONCRETE. Md. M. Hossain 1* , Md. S. Ali 2 , A. Z. Mohammad. Shale 2 1 Department of Civil Engineering, Presidency University, Dhaka, Bangladesh Email: [email protected] 2 Department of Civil Engineering, Presidency University, Dhaka, Bangladesh Email: [email protected], [email protected] * Md. M. Hossain ABSTRACT Compressive strength is affected while concreting in hot weather condition. To increase compressive strength and durability of concrete in hot weather, fly ash are usually incorporated in it. On other hand fly ash replacing Portland cement less CO2 will be released. The objective of this paper is to investigate the effect of fly ash as replacement of cement of concrete. Fly ash minimizes the problem posed by free lime in concrete also increase compressive strength and durability. Moreover it acts as a substitute of cement in concrete, saving cost and making concrete greener by reduce CO2 production. Uses of fly ash are environmental benefits. The test result revealed that for lower concentration (5% - 25%), fly ash acts as accelerating agent and for higher concentration (over 25%), fly ash acts as retarding agent of compressive strength and durability. Optimum concentration was found to be 25%. Addition of fly ash reduced the shear strength of concreate. Keywords: Fly Ash, Ecofriendly, Pozzolanic materials, Workability, compressive strength, Economic. INTRODUCTION The strength of concrete is essential to develop the construction industries, eco-friendly and economical construction. Cement is used to gain high strength for concrete. This demand of high early strength gain of concrete put forth the use of low w/c ratio. Fly ash minimizes the problem posed by free lime in concrete also increase compressive strength and durability. Fly ash acts as a substitute for cement in concrete, saving cost and making concrete greener by reducing CO2 production. Uses of fly ash are environmental benefits. Fly ash is pozzolanic materials also it increases the compressive and durability of concrete. The use of the high volume fly ash cements improves the resistance of the concrete to the chloride ion penetration. The present study investigates the potential of fly ash as the cement replacement in concrete. The objectives are to reduce the amount of ordinary Portland cement needed in building construction so as to achieve economic construction and sustainable development through the preservation of the environment. A. K. Mathu, Izhar Ahmed (Nov-Dec. 2012), Sarath Chandra Kumar October, 2011, Bouzouboa, (2004). Mir Md Tamim, Arindam Dhar, Md. Shahadat Hossain (june 2013). Effect of the fly ash on workability, setting time, density, and air content, and compressive strength, modulus of elasticity, shrinkage and permeability by Rapid Chloride Test (RCPT). In their study 20%, 30%, 40% and 50% replacement of fly ash by mass of cement were made for concrete mixes with 300 to 500 kg/cum cementitious material. Also compressive strength, W/C curves have been plotted for concrete mixes of grade M 15 to M 45 with different percentages of fly ash can be directly designed. Amit Mittal, (2011). 1st International Conference on Research and Innovation in Civil Engineering (ICRICE 2018), 12 –13 January, 2018, Southern University Bangladesh (SUB), Chittagong, Bangladesh ISBN: 978-984-34-3576-7
Transcript of EFFECT OF FLY ASH ON COMPRESSIVE STRENGTH AND …€¦ · EFFECT OF FLY ASH ON COMPRESSIVE STRENGTH...
EFFECT OF FLY ASH ON COMPRESSIVE STRENGTH AND
WORKABILITY OF CONCRETE.
Md. M. Hossain1*, Md. S. Ali2, A. Z. Mohammad. Shale2
1Department of Civil Engineering, Presidency University, Dhaka, Bangladesh
Email: [email protected]
2Department of Civil Engineering, Presidency University, Dhaka, Bangladesh
Email: [email protected], [email protected]
*Md. M. Hossain
ABSTRACT
Compressive strength is affected while concreting in hot weather condition. To increase compressive
strength and durability of concrete in hot weather, fly ash are usually incorporated in it. On other hand
fly ash replacing Portland cement less CO2 will be released. The objective of this paper is to investigate
the effect of fly ash as replacement of cement of concrete. Fly ash minimizes the problem posed by free
lime in concrete also increase compressive strength and durability. Moreover it acts as a substitute of
cement in concrete, saving cost and making concrete greener by reduce CO2 production. Uses of fly ash
are environmental benefits. The test result revealed that for lower concentration (5% - 25%), fly ash
acts as accelerating agent and for higher concentration (over 25%), fly ash acts as retarding agent of
compressive strength and durability. Optimum concentration was found to be 25%. Addition of fly ash
reduced the shear strength of concreate.
Keywords: Fly Ash, Ecofriendly, Pozzolanic materials, Workability, compressive strength, Economic.
INTRODUCTION The strength of concrete is essential to develop the construction industries, eco-friendly and economical
construction. Cement is used to gain high strength for concrete. This demand of high early strength gain
of concrete put forth the use of low w/c ratio. Fly ash minimizes the problem posed by free lime in
concrete also increase compressive strength and durability. Fly ash acts as a substitute for cement in
concrete, saving cost and making concrete greener by reducing CO2 production. Uses of fly ash are
environmental benefits. Fly ash is pozzolanic materials also it increases the compressive and durability
of concrete.
The use of the high volume fly ash cements improves the resistance of the concrete to the chloride ion
penetration. The present study investigates the potential of fly ash as the cement replacement in
concrete. The objectives are to reduce the amount of ordinary Portland cement needed in building
construction so as to achieve economic construction and sustainable development through the
preservation of the environment. A. K. Mathu, Izhar Ahmed (Nov-Dec. 2012), Sarath Chandra Kumar
October, 2011, Bouzouboa, (2004). Mir Md Tamim, Arindam Dhar, Md. Shahadat Hossain (june
2013).
Effect of the fly ash on workability, setting time, density, and air content, and compressive strength,
modulus of elasticity, shrinkage and permeability by Rapid Chloride Test (RCPT). In their study 20%,
30%, 40% and 50% replacement of fly ash by mass of cement were made for concrete mixes with 300
to 500 kg/cum cementitious material. Also compressive strength, W/C curves have been plotted for
concrete mixes of grade M 15 to M 45 with different percentages of fly ash can be directly designed.
Amit Mittal, (2011).
1st International Conference on Research and Innovation in Civil Engineering (ICRICE 2018), 12 –13 January, 2018, Southern University Bangladesh (SUB), Chittagong, Bangladesh ISBN: 978-984-34-3576-7
The main objective of this study is to investigate the possibilities of using fly ash as replacement of
cement. The specific objective of this study is to determine the optimum percentage of fly ash as instead
of cement and its effect on compressive strength and durability. Moreover, increase uses of industrial
waste as a concrete ingredient.
METHODOLOGY
Compressive strength or compression strength is the capacity of a material or structure to withstand
loads tending to reduce size. To investigate the effect of fly ash as replacement of cement, normal
consistency test was undertaken according to ASTM C187. After completing normal consistency test,
with the known consistency (water/cement ratio) eight samples were tested to measure durability
according to ASTM C191. At first, one sample was tested without adding fly ash to the mixture (control
specimen). Then durability was recorded, to know the actual situation of the cement. Then rest 7
samples were tested with different concentration of fly ash, added to the mixture by mixing with water
as a percentage of cement. The concentrations of fly ash were taken as 5%, 10%, 15%, 20%, 25%, 30%
and 35%. Then for all percentage of fly ash, according to ASTM C109, cube specimens were casted
and tested for different ages of curing (1, 3, 7, 14, 21, and 28 days). Then all compressive strength
results were compared with the control specimen.
The durability of concrete depends on its resistance to access of aggressive agents through the pores.
The effect of fly ash on the durability of concrete was investigated. We have casted cubes of size
150×150×150 mm. Following material proportion and various dosage combination of admixture for
0.35 w/c ratio have been studied. For nominal mix of M25 grade of concrete (1:1:2). Fly ash as
replacement of cement 5%, 10%, 15%, 20%, 25% and 30% by weight of cement.
Figure 1, slump with different proportion of fly ash.
Figure 2, Average Compressive strength vs percentage of fly ash.
0
10
20
30
40
0 5 10 15 20 25 30 35
Slu
mp i
n m
m
Percentage of fly ash with cement
0
10
20
30
40
50
0 5 10 15 20 25 30 35 40
Aver
age
Com
pre
ssiv
e
stre
ngth
(M
Pa)
Percentage of fly ash
3 Days
7 Days
14 Days
21 Days
28 Days
1st International Conference on Research and Innovation in Civil Engineering (ICRICE 2018), 12 –13 January, 2018, Southern University Bangladesh (SUB), Chittagong, Bangladesh ISBN: 978-984-34-3576-7
Table -1 the compressive strength of concrete
with different w/c ratio.
Water
Cement
Ratio
Compressive
Strength
MPa
Average
Compressive
Strength
MPa
0.30
30.5
28.4 27.7
27
0.35
27.5
26.5 24.75
26.5
0.40
21.9
22.74 23.32
23
0.45
20.62
20.87 20.90
21.15
0.50
10
12 11.25
14.75
Average values for n = 3
Table -2 slump of concrete with different w/c
ratio.
Water
Cement
ratio
0.30
0.35
0.40
0.45
0.50
Slump In
mm
00 30 35 90 165
Table -3 slump with different percentage of fly
ash of concrete.
Table-4 Compressive strength for different
percentage of fly ash of concrete after different
ages.
Average values for n = 3
RESULT AND DISCUSSION
In this research we show the effect of fly ash on the properties of concrete, which has been investigated in
laboratory and result obtained. The study has been carried out by preparing concrete cubes for 0%, 5%,
10%, 15%, 20%, 25% and 30% replacement of fly ash with the weight of cement and tested after 3, 7, 14,
21 and 28 days of curing. Moreover, we also study of variation in slump for different w/c ratio. Slump lose
for 0.30, 0.35, 0.40, 0.45 and 0.55 w/c ratio respectively. For 0.35 w/c ratio concrete does not show fluidity.
In this we observed that fluidity of concrete increases with the increment in w/c ratio. Table 1 and 2 shows
experimental results.
Percentage
of fly ash
with
cement
0
5
10
15
20
25
30
Slump in
mm
0
2
8
17
20
29
27
Per
centa
ge
of
fly a
sh
Average Compressive strength**
(MPa)
3
Days
7
Days
14
Days
21
Days
28
Days
0* 22 22.3 27.5 30.3 35.08
5 24.06 23.4 30.09 32.02 36.2
10 21 27.19 32.5 34 40.2
15 21.5 28.7 34 37.76 43.2
20 26.90 30 35.5 41 42.7
25 29.57 31.5 39.04 46 45.6
30 24.23 27.09 36.07 35.39 36.75
35 16.40 22.19 22 33 33.05
*Control specimen
**Average compressive strength
1st International Conference on Research and Innovation in Civil Engineering (ICRICE 2018), 12 –13 January, 2018, Southern University Bangladesh (SUB), Chittagong, Bangladesh ISBN: 978-984-34-3576-7
CONCLUSIONS The outcome of research is discussed below.
The normal consistency was 0.35 for normal Portland cement.
Compressive strength was increasing slowly higher than 20% of fly ash.
The 28 days compressive strength with (5-25%) fly ash instead of cement higher than the normal
concrete. But after 25% replacement of cement with fly ash the ultimate compressive strength reduce.
The optimum concentration was found to be 25%.
Slump loss of concrete goes on increasing with the increase of the quantity of fly ash.
The initial slump cannot be measured by slump cone test as it is very less for 0.35 w/c ratio.
ACKNOWLEDGMENTS
First of all, we would like to thank Allah for endowing us with knowledge, health and patience to
accomplish this work. We also acknowledge, with deep appreciation and gratitude, the encouragement,
inspiration, guidance and valuable time given to us by Mr. Abul Fazal Mazumder, Lecturer, Department of
Civil Engineering, Presidency University, Dhaka, Bangladesh. We also very much thankful to Engr. S. M.
Tanjid Ahmed. Finally, we would like to express our deepest gratitude to Shikal Baha Power Station,
Bangladesh Power Development Board,Chittaogong, Bangladesh.
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1st International Conference on Research and Innovation in Civil Engineering (ICRICE 2018), 12 –13 January, 2018, Southern University Bangladesh (SUB), Chittagong, Bangladesh ISBN: 978-984-34-3576-7
