Post on 15-Apr-2017
transcript
By
RIYADH AUDA ISSA ALBATTAT
ID Number: 9513639015
Faculty of Engineering
MIX DESIGN OF AN ACID RESISTANCE CONCRETE USING SILCA FUME
Supervisor
Dr. Zahra Jamshidzadeh
Advisor
Dr. Ali Al-Asadi
1. Definition of the Problem
2. Main Objectives
3. Literature Reviews
4. Experimental Work Description
5. Future Results
6. Conclusions
Outlines
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Traditionally, Ordinary Portland cement
is used for making the civil structures.
Portland cement can be partially
replaced by silica fume. Silica fume is
non metallic and non hazardous waste
of industries.
Figure 1: Ordinary Portland Cement
Definition of the Problem
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Concrete has been considered as a basic
material that is involved in the built
environment around the world (Aitcin,
2000) being used to build our schools,
hospitals, homes, bridges, sewage
systems, roads and more. Corrosion of
concrete sewer pipes induced by
sulphuric acid attack is a recognized
problem worldwideFigure 1: Corrosion of a concrete sewer pipe
Definition of the Problem
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Corrosion of concrete sanitary sewers due to
biogenic acid formation is a major problem for
sanitation districts in many parts of the world.
Sewage system materials can experience
aggressive acid corrosion and significant
nuisance odor. Corrosion can reduce
collection system asset life and increase
funding requirements associated with
rehabilitation and replacement.
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The most common and
destructive corrosion
problem is in the
underground concrete
sewer structures of Iraq
which is caused by
biogenic sulfuric acid
attacks.
However, sulfuric acid may exist in
different places, such as in
underground water and industrial
waste, and can be very harmful for
concrete structures that come into
contact with it.
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The originality of this study rests on the following pillars:
1. Evaluate the optimum silica fume controlling the compressive
strength of concrete.
2. Investigating the effect of suphuric acid environments on the
concrete strength at different silica fume replacement.
3. Conducting an extensive experimental to determine the changes in
weight, compressive strength and visual appearance of the
specimens as a measure of its resistance against acid.
Main Objectives
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Concrete structures, such as manholes and sewer pipes, contain
considerable amounts of liquid waste which make them suitable
places for anaerobic bacteria to convert dissolved sulfate into H2S.
The reaction that takes place for the production of H2S gas by the
SRB in sewer pipes is as
follows (Kaempfer and Berndt 1999):
Literature Review
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It should be noted that the rate of the deterioration of concrete
structures close to groundwater is dependent on the concentration
of the sulfuric acid and the amount of water that can reach the
concrete surface. The permeability of the soil that is in contact with
concrete also plays an important role (Skalny et al. 2002).
Literature Review
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Mehta (1985) reported that replacing Portland cement with 15%
silica fume would improve the resistance of concrete to a 1%
sulfuric acid solution. In this study, cylindrical specimens were
submerged into a sulfuric acid solution and their weight was
measured every week after the removal of loose particles from their
surfaces by using a steel wire brush. A better performance of the
concrete which contains micro silica was attributed to less Ca(OH)2
and more C-S-H phases in its structure.
Literature Review
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On the other hand, the studies of Monteny et al. (2003)
on different concrete mixtures showed that concrete
mixture with 8.6% silica fume does not perform very
well in terms of resistance to 0.5% sulfuric acid. In
their studies, a special kind of apparatus was used to
expose the concrete cylinders to the 0.5% sulfuric acid
solution. As illustrated in Figure 4, concrete cylinders
were subjected to cycles of immersion in sulfuric acid
solution and dried in air by rotation on horizontal axes
Literature Review
Figure 4: Apparatus for accelerated
degradation testing
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Experimental Work Description
1- Materials
• Portland Cement:
Ordinary Portland Cement confirming to IQS: 5-1985 was used in the
present study.
• Fine Aggregates:
Iraqi fine aggregate confirming to IQS: 45 was used in the present study.
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Experimental Work Description
• Coarse Aggregates:
Crushed aggregate confirming to IQS: 5-1985 was used.
• Water:
Water conforming to as per IQS: 456 was used for mixing as well as
curing of concrete.
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Experimental Work Description
• Sulphuric Acid:
Sulphuric acid solution (pH=2.0-3.0)
is used in this study).
• Chemical Admixtures:
MC55. was used in this study as the
SP. An AEA is also used. The
properties of these admixtures are
provided in Table 1
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Experimental Work Description
• Silica Fume:
Silica fume is simply a very
effective pozzolanic materials.Silica
fume was procured from Iraq,
Baghdad. The Silica fume is used as
a partial replacement of cement.
The chemical composition of silica
fume is listed in Table 2:
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Table 2: typical properties of Silica Fume at 25 oC
Experimental Work Description
Design and Placing of Concrete Mixtures
Three concrete mixtures (C15, C25, C45) is designed with different
silica fume percent (4%, 8%, 15% and 20%).
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Future Results
• Effect of silica fume on compressive strength.
• Effect of sulphuric acid on compressive strength at
different ages.
• Effect of silica fume on the concrete grade at different
ages
• Comparison between compressive strength at normal and
acid curing at different ages.
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0 5 10 15 20 250
5
10
15
20
25
30
35
Compressive strength in Acid Enviornment
7 (days)14 (days)28 (days)
Silica Fume %
Com
pres
sive
Str
engt
h (M
Pa)
0 5 10 15 20 250
5
10
15
20
25
30
35
Compressive strength in Tap Water Enviornment
7 (days)14 (days)
Silica Fume %
Com
pres
sive
Str
engt
h (M
Pa)
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Conclusions
The following conclusions will be discussed based on the results and analyses
presented in this report.
• The replacement of cement by silica fume and with different
concrete grade.• The effect of acid solutions on the concrete strength at different
silica fume must be studied and discussed.• The maximum loss on the concrete weight should be dicussed at
different silica fume.• The optimum silica fume should be discussed using different
concrete grade at acid and normal curing.
1. Aitcin, P. C 2000. ‘Cements of yesterday and today, concrete of
tomorrow’, Cement and Concrete Research, 30, 1349-1359,
http://www.agnieszka.slosarczyk.pl/serwis/repozytorium/data/tech_bet/
techbet03.pdf>.
2. Kaempfer, W., and M. Berndt. "Estimation of service life of concrete pipes in
sewer networks.“ Proceedings of Durability of Builiding Materials and
Components 8 (1999): 37-45.
Figure 2: FRP Piling Tubes
References
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3. Skalny, Jan, Jacques Marchand, and Ivan Odler. Sulphate attack on concrete.
London and New York: Spon Press, 2002.
4. Mehta, P.K. "Studies on chemical resistance of low water/cemet ratio
concretes." Cement and Concrete Research 15, no. 6 (1985): 969-978.
References
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