ACID RESISTANCE CONCRETE USING SILCA FUME

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


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 worldwideFigure 1: 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.


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.


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


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


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


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


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.



• 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



• 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:


Table 2: typical properties of Silica Fume at 25 oC


Design and Placing of Concrete Mixtures

Three concrete mixtures (C15, C25, C45) is designed with different

silica fume percent (4%, 8%, 15% and 20%).



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.


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)


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


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


ACID RESISTANCE CONCRETE USING SILCA FUME

Engineering

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