Mix Design Acid Resistance Concrete using Silcafume

By
RIYADH AUDA ISSA ALBATTAT
ID Number: 9513639015
Faculty of Engineering
MIX DESIGN OF AN ACID RESISTANCE CONCRETE
USING SILCA FUME
Supervisor 1
Dr. Zahra Jamshidzadeh
Supervisor 2
Dr. Ali Al-Asadi

1. Definition of the Problem
2. Statement of the Problem
3. Main Objectives
4. Literature Reviews
5. Experimental Work Description
6. Future Results
7. Conclusions
Outlines

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

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
worldwide
Figure 2: Corrosion of a concrete sewer pipe
Definition of the Problem

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.
Figure 3: Mechanism of H2SO4
Production in Sewers (Sand, 1994)

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 and nitric acids
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.

Statement of the Problem
Iraqi sewer system is a typical
example of such problem in which
there is work that is currently
being undertaken on the
performance of sewer pipe
concrete materials. Figure 4 shows
an example of deteriorated
concrete due to exposure in a ‘live
sewer’ for a period of more than 20
years. Figure 4.: Degradation in sewer system in
Al-Nassiriyah city

Figure 5.: Site location on Iraq map
Problem Location
Nasiriyah city is an industrial city on
the south of Iraq (365 km towards in
Baghdad). Due to the sewage
environmental conditions, it
qualifies as an aggressive
environment. Further, the location of
several industries, particularly
petroleum refinery, makes it a very
suitable site for this investigation

The originality of this study rests on the following pillars:
1. To investigate the suitability of silica fume by replacing
cement with silica fume at varying percentage on concrete
that exposed in aggressive environment and compared with
conventional concrete.
2. To evaluate the optimum silica fume replacement percentage
for obtaining maximum strength for control and silica fume
concrete subjected different curing conditions.
Main Objectives

3. To evaluate the effect of curing on the strength weight loss
characteristics of plain and silica fume concrete exposed to
a an aggressive environment, as a model for concrete in
sewage system application.
4. To make recommendations on the use of silica fume concrete
that used in sewage applications in Iraq climates, and more
specifically in Al-Nassiriyah city.
Main Objectives

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

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

Cohen and Bentur, 1990 investigated the effect of 15% silica fume
replacement of Types I and V Portland cement on the resistance to
sulphate attack in magnesium and sodium sulphate solutions.
Literature Review
Sellevold and Nilsen, 1987 have found field studies of concretes with and
without 15% silica fume. After 20 years' exposure to ground water
containing 4 g/L sulphate and 2.5–7.0 pH, the performance of the silica
fume concrete was found equal to that of the concretes made with
sulphate-resisting Portland cement, even though the water/cementitious
materials ratio was higher for silica fume concrete (0.62) than for control
(0.50).

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.
• 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.

• 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.
Figure 6.: Silica Fume

• Aggressive Acid
(Sulphuric and Nitric)
Aggressive acid solution (2%
Sulphuric acid and 2% Nitric
Acid) (pH=1.75-2.25) was used
in this study).
Figure 7 :Sulphuric and Nitric Acids Containers

Figure 8: Experimental program for specimens
cured in Tap

Figure 9 .: Experimental program for specimens
cured in aggressive acid water

Mixing of Concrete Mixtures
Three concrete mixtures (C15, C25,
C45) is designed with different silica
fume percent (4%, 8%, 15% and 20%).

Results and Discussion
1- Effect of SF on Compressive Strength
0
5
10
15
20
25
30
35
40
0 20 40 60 80 100
CompressiveStrength(MPa)
Age (days)
0% Silica Fume
4% Silica Fume
8% Silica Fume
15% Silica Fume
20% Silica Fume
0
5
10
15
20
25
30
35
40
45
50
0 20 40 60 80 100
Age (days)
0% Silica Fume
4% Silica Fume
0
10
20
30
40
50
60
0 20 40 60 80 100
Age (days)
0% Silica Fume
4% Silica Fume
Grade Mix:15 MPa
Grade Mix:25 MPa Grade Mix:45 MPa
Figure 12: Effect of silica fume on compressive
strength of concrete immersed in tap water

Effect of Aggressive Acid
0
5
10
15
20
25
30
35
0 20 40 60 80 100
Age (days)
0% Silica Fume
4% Silica Fume
8% Silica Fume
15% Silica Fume
20% Silica Fume
0
5
10
15
20
25
30
35
0 20 40 60 80 100
Age (days)
0% Silica Fume
4% Silica Fume
8% Silica Fume
15% Silica Fume
20% Silica Fume
0
5
10
15
20
25
30
35
40
45
50
0 20 40 60 80 100
Age (days)
0% Silica Fume
4% Silica Fume
8% Silica Fume
15% Silica Fume
20% Silica Fume
Figure 13: Effect of silica fume on compressive strength of concrete
immersed in aggressive acid
Grade Mix:25 MPa
Grade Mix:15 MPa
Grade Mix:45 MPa

Weight Loss
0
5
10
15
20
25
0 4 8 15 20
WeightLoss(%)
Silica Fume (%)
In Tap Waterl
In Acid
0
5
10
15
20
25
0 4 8 15 20
WeightLoss(%)
Silica Fume (%)
In Tap Waterl
In Acid
0
5
10
15
20
25
0 4 8 15 20
WeightLoss(%)
Silica Fume (%)
In Tap Waterl
In Acid
Grade Mix:15 MPa
Grade Mix:25 MPa
Grade Mix:45 MPa
Figure 413: Weight loss percentages in control and
acid cured specimens with different quantities of
silica fume

Effect of Curing Time
0
5
10
15
20
25
30
35
40
0 5 10 15 20 25
Silic fume (%)
7 days
14 days
28 days
90 days
0
5
10
15
20
25
30
35
0 5 10 15 20 25
Silica fume (%)
7 (days)
14 (days)
28 (days)
90 days
Figure 15: Effect of silica fume (SF) content on the
compressive strength for C15
In Aggressive acidIn Tap water

Effect of Silica Fume on Concrete Grade
Figure 16: Relationship between 28 day compressive
strength and percentage replacement of silica fume
0
10
20
30
40
50
60
0 5 10 15 20 25
SF %
(w/c)=0.55
(w/c)=0.51
(w/c)=0.40

Comparison Between Present Study and Others
0
10
20
30
40
50
60
0 5 10 15 20 25 30
SF (%))
Present Study
Vishal et al.,(2017)
Ghutke et al.,(2014)
Figure 17: Relationship between 28 day compressive strength and percentage
replacement of silica fume for grade 25 MPa

Visual Inspection
a- Concrete specimen for low grade (C15)
b- Concrete specimen for low grade (C25)
c- Concrete specimen for low grade
(C45) immersed in aggressive acid
Figure 18: Visual assessment of degraded concrete samples for different
grades after 12 weeks of exposure to aggressive acid solution

Conclusions
The following conclusions will be discussed based on the results and analyses
presented in this report.
1. The Sf concrete mixes had higher strength compound to the control plain
mixes at SF percentage 15% .
2. Generally, there is a decrease in mass of SF concretes in aggressive acid
environment.
3. Most of the experimental work was performed in laboratories on control
specimens which were prepared and cured under normal curing conditions.
This experimental work was different from those on a typical work, where the
concrete is exposed to aggressive acid to simulate the concrete sewage
construction.
4. The majority of research work carried out has been devoted to the effect of
aggressive acid on silica fume concrete compressive strength.

5- In hot Middle Eastern countries such as Iraq, where the average temperature is
often over 35oC during several months of the year, the inclusion of pozzolanic
materials such as silica fume may show advantageous results in terms of strength
and durability compared to plain Portland cement Thus, information on how
simulated sewage system environments and curing time can affect properties of
these modified concretes needs to be investigated urgently.
6- The results of this experimental works show that the increase in w/c ratio with
silica fume, strength of concrete decreases.
7-The results of this investigation show that mix design parameters, namely,
water-cement ratio, silica fume, percentage, age and curing significantly
influence the strength and durability characteristics of plain and silica fume
cement mortars.
9- From the side of visual assessment, it can be seen that the aggregates are
completely exposed in all the specimens, but there are some significant differences
between the mixtures in this regard. It is interesting to observe that the severity of
degradation for low grade concrete is so high than medium and high grade
concrete

Recommendations for further research work
1. The Experimental work here revealed the optimum concrete strength in the
content (15% by weight of OPC) -silica fume concrete subjected to different
conditions. These concrete mixtures need to cure at more type of aggressive
and alkaline acids. Therefore, further research work is needed to explain fully
behaviour of concrete.
2- In this work the effect of silica fume was investigated by-subjecting concrete
specimens to two different curing conditions. It would be of interest to study
the effect of temperature and humidity separately to evaluate which parameter
is having the greatest effect.
3- Since the concrete mixtures at different grades mixing with different percent of
silica fume is the main study. It would be very interesting to study the
reinforcement concrete to evaluate the corrosion in the steel.

Mix Design Acid Resistance Concrete using Silcafume

Mix Design Acid Resistance Concrete using Silcafume

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