UTeM Library (Pind.112007)
& L * Y S l 4
$P-y$
UNlVERSlTl TEKNIKAL MALAYSIA MELAKA -
-
-
--
-
T C i d k Q S Z (A@GJU C \ ; c W o L I
SESl PENGAJIAN : 1uc7 -- Lit
B
8
Saya
C
ilkd?C-W@
ScoU
mengaku membenarkan tesis (PSMISarjanalDoktor Falsafah) ini disimpan di Perpustakaan Universiti Teknikal Malaysia Melaka (UTeM) dengan syarat-syarat kegunaan seperti berikut:
1. Tesis adalah hak milik Universiti Teknikal Malaysia Melaka
.
2. Perpustakaan Universiti Teknikal Malaysia Melaka dibenarkan membuat salinan untuk tujuan pengajian sahaja.
3. Perpustakaan dibenarkan membuat salinan tesis ini sebagai bahan pertukaran antara institusi pengajian tinggi.
4. **Sila tandakan
(d)
SULlT atau kepentingan Malaysia yang termaktub di dalam (Mengandungi maklumat yang berdarjah keselamatan AKTA RAHSIA RASMl 1972)
TERHAD (Mengandungi maklumat TERHAD yang telah ditentukan
oleh organisasilbadan di mana penyelidikan dijalankan) TlDAK TERHAD
Disahkan oleh:
(is
(TANDATANGAN PENULIS)
MOHD. ASYADI ' A U M BIW MOHB. ABI,
Alamat Tetap: Rasmi: Fakub K,ruteraan Pensyarah Permuah"
- (
PRDC
,3im
fduDOUR
1 h ~ e r s l f l Te~nlkal Maliiysla Melaka Karung Berkunc~ 1200 Ayer KerohPEP
i~ \<
75450 h l a k aTarikh: ~ ~ - k l ~ b ~ Tarikh:
23
' 4 . J C L0 ~Tesis dimaksudkan sebagai tesis bagi ljazah Doktor Falsafah dan Sarjana secara penyelidikan, atau disertasi bagi pengajian secara kerja kursus dan penyelidikan, atau Laporan Projek Sarjana Muda (PSM).I
DECLARATION
I hereby, declare this thesis entitled "Corrosion Behaviour of
Steel for Simulated Concrete in Chloride Aqueous Solution"
is the result of my own research
except as cited in the references.
Signature
...
(%-.
(- k\litd?
C
0u u
Author's Name :
...
APPROVAL
This PSM submitted to the senate of UTeM and has been as partial fulfillment of the requirements for the degree of Bachelor of Manufacturing Engineering (Materials
Engineering). The members of the supervisory committee are as follow:
(Main Supervisor: Mohd. Asyadi 'Azam bin Mohd. Abid) (Official Stamp & Date)
MOHD. ASYADI ' A U M BIN MmHD. M I D
Pensyarah
Fakulti Keiurutenan Pernbuatan Univers~ti Tennikai Malaysia Metaka
Karuna Berkunc~ 1200, Ayer Keroh
Co-Supervisor (Oficial Stamp & Date)
MOHAMAD HAlDlR BIN MASLAN
Tutor
Fakulti Kejun~teraan Pembuatan Universili Tekntkal Malaysia Melaka
ABSTRACT
ABSTRAK
ADKNOWLEDGEMENT
First, I would like to express my sincere and appreciation to my supervisors,Mohd Asyadi Azam Bin Mohd Abid who always have been providing guidelines and related information for the completion of the thesis. He has shown great faith in me and has been very supportive throughout the research. In addition, not forgetting to extend my gratitude to University Tun Hussein OM (UTHM) and their technicians where I carried on my research. To staffs of Ann Joo Steel Berhad who is willing to send me some raw material for the research. Furthermore, I would like to express my appreciation to technicians in polymer lab and material lab who willing to share their knowledge to me during the research. Also, not forgetting to express my sincere to all lecturers of Manufacturing Engineering Faculty (FKP),UTeM for their nurturing.
TABLE OF CONTENTS
Abstract
...
.i. .
Abstrak...
.ii...
Dedication...
ill Acknowledgment...
.ivTable of Contents
...
..vList of Figures
...
..ixList of Tables
...
xi. .
List of Abbrebiations, Symbols, Specialized Nonmenclature...
xi11. INTRODUCTION 1 .I Background
...
.11.2 Problem Statements
...
.2...
1.3 Objectives 3 1.4 Scope of Study...
.32. LITERATURES REVIEW 2.1 Electrochemical Theory of Corrosion
...
..52.2 Type of Concrete
...
..62.2.1 Cement
...
82.2.2 Water
...
92.2.3 Aggregates
...
.92.2.4 Admixtures
...
102.3 Type of Steels
...
.I0 2.3.1 Carbon Steels or Unalloyed Steels...
112.3.1.3 High Carbon Steels
...
122.3.1.4 Ultra Carbon Steels
...
122.4 Mechanisms and Principal of Reinforcement Corrosion in Concrete
...
122.4.1 General Aspects
...
122.4.1.1 Stages in the Deterioration Process
...
14(a) Initiation Stage
...
15@) Propagation Stage
...
162.4.2 Chloride Induced Corrosion
...
172.4.2.1 Pitting Corrosion
...
182.4.2.2 Chloride Induced Corrosion Initiation
...
202.4.2.3 Chloride Threshold Level
(CTL)
...
222.4.2.4 Penetration of Chloride
...
232.4.3 Electrochemical Aspects
...
272.4.3.1 Electrochemical Mechanism of Corrosion
...
272.4.3.2 Concrete Containing Chlorides
...
30(a) Corrosion Initiation and Pitting Potential
...
30@) Propagation
...
312.4.4 Corrosion Behaviour of Steel Reinforced Concrete-Corrosion Rate
...
322.4.4.1 Factors Mecting of Corrosion Rate
...
33(a) Concrete Cover Thickness
...
33@) Aggressiveness Condition
...
35(c) Cracks
...
362.4.4.2 Corrosion Rate Measurement-Tafel Plot Technique
...
372.4.4.3 Corrosion Rate Measurement-Linear Polarization Resistance (LPR)
...
382.4.5 Corrosion Behaviour of Steel Reinforced Concrete-Morphology
...
402.5 Other Type of Reinforcement Corrosion
...
412.5.1 General Corrosion
...
412.5.3 Concentration Cells
...
432.5.4 Differential-Oxygen Cells
...
432.5.5 Dissimilar Metal Corrosion or Galvanic Cells
...
44...
2.5.6 Stray Current 44 3.
METHODOLOGY...
45...
3.1 Introduction 45 3.2 Process Sequence...
463.3 Steel Bar Preparation
...
473.4 Formwork Frame
...
493.5 Mix and Form Reinforced Concrete
...
533.6 Electrochemical Testing and Measurement
...
57...
3.6.1 Electrolyte 57 3.6.2 Electrodes...
57...
3.6.3 Testing Program 59 3.7 Microstructure or Morphology Observation...
624
.
EXPERIMENTAL RESULTS AND DISCUSSIONS...
654.1 Anodic Polarization Curve
...
-654.1.1 Sodium Chloride Aqueous (1%)
...
654.1.2 Sodium Chloride Aqueous (3%)
...
674.1.3 Sodium Chloride Aqueous (5%)
...
694.1.4 Sodium Chloride Aqueous (7%)
...
714.1.5 Comparison between 1%.3%. 5% and 7% wt NaCl
...
744.2 Corrosion Resistance
...
774.3 Corrosion Rate
...
784.4 Microscopic
...
804.4.1 Scanning Electron Microcopy (SEM)
...
804.4.2 Optical Microscope (OM)
...
..855. RECOMMENDATION AND CONCLUSION
5.1 Recommendation
...
89 5.2 Conclusion...
.90REFERENCES
...
.92APPENDICES
A Gantt Chart for PSM I
B Gantt Chart for PSM I1
C Tafel Plot for Specimen in 1% wt Sodium Chloride Solution
D
Tafel Plot for Specimen in 3% wt Sodium Chloride SolutionE Tafel Plot for Specimen in 5% wt Sodium Chloride Solution
F
Tafel Plot for Specimen in 7% wt Sodium Chloride SolutionLIST
OF
FIGURES
Cross Section of Steel Bar and Concrete Portland Cement
Corrosion in Reinforced Concrete
Initiation and Propagation Periods for Corrosion in a Reinforced Concrete
Pitting Corrosion of Steel in Concrete
Schematic Representation of the Process of Corrosion Initiation Arising from Chloride Ions
Corrosion Initiation Evident from the Corrosion Product on the Concrete Surface at the Location of a Void
Corrosion Mechanism for Concrete Containing Ion Chloride The Corrosion Process for Steel in Concrete
Electrochemical Mechanism of Corrosion of Steel in Concrete Example of the anodic polarization curve of steel in concrete with different aggressive ions
Reduction of the Initiation Time of Corrosion due to Reduction in Concrete Cover Thickness
Example of Bacteria Corrosion
The Whole Process Sequence in Project Corrosion Study Low Carbon Steel Deformed Bars (MS 146:2000) US Portable Cleaner (JEIOTECH LAB COMPANION) Process Flow for Low Carbon Steel Deformed Bar Preparation Concept for Formwork Frame Setting Process
Formwork Frame
Concept for Concrete Mixing Process
Process Sequence for Mix and Form Reinforced Concrete Schematic for Reinforced Concrete
Reinforced Concrete Specimen Reference Electrode
Counter Electrode
PGSTATlOO Potentiostat
Set up for Polarization Test and Corrosion Rate Measurement Schematic Diagram of Test Setup for Corrosion Rate Measurement Process Sequence for Electrochemical Test and Measurement Optical Microscope (CARL ZE1SS:Axioskop 2 MAT,2003) Scanning Electron Microscope (CARL ZEISS EVO 50) Process sequence for Morphology Observation
Anodic Polarization Curve of Low Carbon Steel in Concrete in Aqueous Solution with 1% wt Sodium Chloride
Anodic Polarization Curve of Low Carbon Steel in Concrete in Aqueous Solution with 3% wt Sodium Chloride
Anodic Polarization Curve of Low Carbon Steel in Concrete in Aqueous Solution with 5% wt Sodium Chloride
Anodic Polarization Curve of Low Carbon Steel in Concrete in Aqueous Solution with 7% wt Sodium Chloride
Anodic Polarization Curve of Low Carbon Steel in Concrete with Difference Weight Percentage (I%, 3%, 5 % &7%) of Sodium Chloride Aqueous Solution
4.6b Morphology (SEM) of the Rebar Surface after Anodic Polarization
Test in 1 %(i), 3%(ii), S%(iii) and 7%(iv) Sodium Chloride 82 4.7a Microscopic of the rebar surface before anodic polarization
test under magnification 500X 85
4.7b Morphology (OM) of the rebar surface after polarization
LIST
OF
TABLES
2.1 Minimum Values for Concrete Cover Depth, Simplified from
Eurocode 2 with Regard to Corrosion Protection of Steel for Structure Class 4 and Exposure Classes defined by EN 206.These Values should be increased by 10mm to obtain the Nominal Cover Depth. 34
3.1 Composition of Low Carbon Steel Deformed Bar (MS 146:2000) 48
4.1 Electrochemical data for rebar in concrete specimens placed in
sodium chloride aqueous solution at I%, 3%, 5% and 7% C1- 77 4.2 Corrosion rates obtain by extrapolation of Tafel plot after
17 minutes exposure 78
LIST OFABBREBIATIONS, SYMBOLS, SPECIALIZED
%
f A A h 2 ASTM B ba bc BS BSI C c1- CR
G
CTL
cx
D ~ P P
%i&b Em, erfc EW Fe Fe(OH)2 Fe(OH)3
NOMENCLATURE
-Ampere per centimeter square
-
American Standard Testing Method- Stern-Greary Constant.
- Slope of the anodic Tafel reaction
- Slope of the cathodic Tafel reaction
-British Standards
-British Standards Institution -Carbon
-Chloride Ion
- Corrosion Rate
- Surface Chloride Content
- Chloride Threshold Level
-
Total Chloride Content (% by mass of cement or concrete)-
Apparent Diffusion Coefficient for Chloride (m2/s)- Pitting Potentialbreakdown potential -Corrosion potential
- Error Function
- Equivalent Weight
-Ferrite
~ e ~ + ~ e ~ '
Fe304
g
I
T
H20 HCl
1 mr
1, Ic Icon Kg 1 LPR m3 mA/m2 ml mm
m d y MPa
am"
MS Nat
-Ferrite (11) Ion -Ferrite (111) Ion -Ferum(iV)Oxide(III) -Gram
-Hydrogen Ion -Water
-Hydrochloric Acid
-Rate of the overall process of corrosion
-
Anodic current-Cathodic Current
-Current that circulates inside the concrete from the anodic area to the cathodic area
- Corrosion Current Density
- Intensity of the corrosion current
-Current that flow inside the steel from the cathodic area to the anodic
-Kilogram -Little
- Linear Polarization Resistance
-Meter Cubic
-Miliampere per meter square -Mililiter
-Millimeter
-Millimeter per year -Mega Pascal
-Megapascal Root Meter Square
- Malaysia Standard
-Sodium Ion
NaCl 0 2 OH- OM PSM I PSM I1 R.H RP S SCE SEM t
TP
us
USAv
wlc XRD pVcm2- Sodium Chloride -Oxygen
-Hydroxide Ion -Optical Microscope
- Project Sarjana Muda I
- Project Sarjana Muda I1
-Relative Atmospheric Humidity
- Polarization Resistance
-Second
-Saturated Calomel Electrode
- Scanning Electron Microscope
-Time
- Tafel Plot Technique
-United State
-United State American -Volt
-Water over Cement
- X-ray Diffraction
-Micrometer per centimeter square -Micrometer
CHAPTER 1
INTRODUCTION
1 .
Background
Corrosion problem occurred on earth for more than a century. It occupied many fields that have application of metal such as electronic sector, agricultural sector, manufacturing sector and chemical plant. However, corrosion happen in construction field is the most critically because it involves large amount of human that live under these structures.
However, the presence of chloride ions introduced into concrete from contaminated aggregates or water and external environment in excess of a critical threshold level can damaged the passive protection film. After that, the durability of reinforced concrete structures may be drastically limited. This chloride induce corrosion of reinforced concrete structure may often mention on marine structure, both on shore and off shore. It becomes the major cause of the infrastructure deterioration in many parts of the world.
When the corrosion is initiated in reinforced concrete structures, the structures need to be repaired, renewed or replaced within a short period of years. This is extremely expensive, as can be noticed that the remediation of concrete bridges in the USA undertaken as a direct result of corrosion of the reinforcing steel cost the US state departments 5 billion in the year 2000; all forms of corrosion
damage to concrete in UK in 1997 was
f
750million (BCA,2000).1.2
Problem Statements
Concrete essentially take care of compressive stresses but weak in tension. Therefore, steel should embed in concrete to strength its tensile property. The concrete that after embed steel is called as reinforced concrete.
high numbers of structures where corrosion and especially steel reinforcement corrosion has led to premature failures and costly restoration. As the saying state that "prevention is better than cure", it is necessary to understand, study, and prevent the corrosion problem before it occurred.
Corrosion of steel reinforcement in structures is now a feature which figures heavily in the maintenance of existing buildings, contributed to a number of structural collapses and involved large amount of human life. Concrete condition is simulated to investigate the influence of aggressive element such as ion chloride in corrosion of steel in concrete.
1.3
Objectives
The purposes of this project are:
i) To study the effect of different level of chloride content on corrosion rate in steel reinforced concrete.
ii) To compare and study the morphology reinforced steel before and after corrosion based on difference concentration of chloride in concrete.
1.4
Scope of Studies
CHAPTER 2
LITERATURE REVIEW
2.1
Electrochemical Theory of Corrosion
Corrosion can be defined in different ways but the common interpretation of the term is deterioration of a material especially metal by reaction with species in the environment to form chemical compound. The' concept of corrosion can involved wider sense, where attack on non metallic materials. Corrosion of metallic material can be separated into three main groups. The first group is corrosion in other fluid like molten metal and fused salt. The second group is called wet corrosion, where the corrosive environment is water with dissolved species. The liquid is known as electrolyte and it is an electrochemical process at room temperature. The last group of corrosion is involved dry gas corrosive environment. Therefore, this group is known as dry corrosion. This group of corrosion is also often called chemical corrosion or high temperature corrosion.
electrical circuit without any accumulation of charges. Electrode is an electronic conductor which cathodic reaction and anodic reaction happens. Normally, the metal works as electronic conductor. Between the anode and cathode, ionic and must flow to avoid the build up of charge. Therefore, electrolyte is necessary for corrosion process. The electrolyte is usually an aqueous solution of ions such as Na', Cl-, OH-
and ~ e ~ + . The positive ions are called cations and the negative ions are known as anions. If there is no external source of electrons is applied, the consumption of electron in cathode must same rate to the generation of electron in anode. Based on the condition, this dissolution process is called wet corrosion and the mechanism is electrochemical. This electrochemical is occurred in steel reinforced concrete which regarding to this project.
2.2
Q p e
of Concrete
Concrete (Figure 2.1) is a multiphase material construction material containing cement paste (unhydrated and hydrated compounds), water, aggregates (sand and gravel) and sometimes admixtures in required proportions. Concrete solidifies and hardens after mixing and placement due to a chemical process known as hydration. The overall mechanical and physical properties of concrete depend on the volume fraction and properties of the constituents and the mechanisms of interaction between the separate phases.
