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1
DURABILITY of CONCRETE
STRUCTURES
Prof. Dr. Halit YAZICI
Part- I
2
GENERAL KNOWLEDGE
- CONCRETE STRUCTURES SHOULD CONTINUE TO PERFORM
ITS EXPECTED FUNCTIONS (STRENGTH & SERVICEABILITY)
DURING THEIR SERVICE LIFE WITHOUT MAJOR REPEATED
REPAIRS
- ARTIFICIAL CONSTRUCTION MATERIALS ARE USUALLY
UNSTABLE. THEY ARE LIABLE TO CONVERT TO THEIR
ORIGINAL FORMS.
- NATURAL MATERIALS (MILLIONS YEARS OLD) ARE MORE STABLE.
EXAMPLE: NATURAL STONE
EXAMPLE:
IRON OXIDE ENERGY
STEEL RUSTING
IRON OXIDE
3
SYMBOLS OF DURABILITY
ST. SOPHIA (ISTANBUL)
SERVICE LIFE :
537 AC COMPLETION DATE
(941 YEARS CHURCH + 422
YEARS MOSQUE & MUSEUM)
PYRAMIDS
(CHEOPS, KHEFREN,
MYKRENOS)
4500 YEARS OLD
EGYPTIAN PROVERB:
MANKIND IS AFRAID of TIME
TIME IS AFRAID of PYRAMIDS
The Pantheon, called the Temple of the Gods, is one of the greatest engineering wonders of the Roman Empire.
Built in 128 A.D. by Emperor Hadrian, the Pantheon held the world record for the largest dome diameter (43.2m) for almost 1800 years.
Romans made concrete by mixing lime and volcanic ash found in regions around the Gulf of Naples, especially from near the modern-day town of Pozzuoli.
SYMBOLS OF DURABILITY
6
GENERAL KNOWLEDGE
ARTIFICIAL STONE (CONCRETE OR REINFORCED CONCRETE)
NEGATIVE FACTORS DETERIORATION
SERVICE LIFE
PERFORMAN CE Time
Minimum
Before repair
After repair
Before repair
After repair
INITIAL
FINAL
7
BS 7543: Guide to durability of building
elements, products and component
Monumental Constructions, Bridges,
Dams, etc. 100 4
Normal Buildings, Public Buildings 50 3
Demontable Construction elements,
Prefabricated beams, columns, etc. 25 2
ENV 1991-1 = BS 7543 Minimum
service life (year) Example Class
Temporary Buildings 1-5 1
8
Relationship between durability and performance
9
Durability of concrete • Durability of concrete may be defined as the ability of concrete to resist: − weathering action, − chemical attack, and − abrasion while maintaining its desired engineering properties. • Different concretes require different degrees of durability depending on the exposure environment and properties desired. − For example, concrete exposed to tidal seawater will have different requirements than an indoor concrete floor.
10
PHYSICAL & MECHANICAL
DETERIORATION of REINFORCED CONCRETE by
EXTERNAL & INTERNAL FACTORS
CHEMICAL & BIOLOGICAL
CORROSION of REINFORCEMENT
CRACKS SPALLINGS, POP-OUTS
LOSS of STRENGTH & RIGIDITY
DEFORMATIONS
CHANGE OF PORE STRUCTURE, INCREASE in PERMEABILITY
ACCELERATION of DETERIORATION PROCESS
11
PHYSICAL & MECHANICAL FACTORS
CAUSES of MASS LOSS
CAUSES of CRACKS
WEARING, EROSION,
CAVITATION FIRE, HIGH TEMPERATURES
EXCESSIVE LOADING, REPEATED LOADING, FATIQUE LOADING, IMPACT LOADS
FREEZE-THAW, DE-ICING AGENTS, WETTING & DRYING, CHANGE of LENGTH & VOLUME
12
CHEMICAL & BIOLOGICAL FACTORS
-SULFATE ATTACK
-DEF
-THAUMASITE ATTACK
-ASR and ACR
-DELAYED REACTIONS of CaO & MgO
-CORROSION of REINFORCEMENT
I. GROUP
HYDROLYSIS, WASHING OUT
II. GROUP
IONIZATON REACTIONS WITH AGGRESSIVE CHEMICALS
III. GROUP
PRODUCTS of REACTIONS of EXPANSIVE NATURE
REPLACEMENT of Ca++ IONS with
Mg++ in CSH
REMOVAL of Ca++ IONS by
FORMATION of SOLUBLE or UNSOLUBLE PRODUCTS
13
14
PRINCIPLES of CONCRETE DESIGN
FACTORS
WORKABILITY
SLUMP, MIN. ENERGY for COMPACTION, COHESIVENESS, NO SEGREGATION, MIN. BLEEDING, HOMOGENIETY
OPTIMIZATION
PROBLEM
ECONOMY EFFECTIVE USE of SOURCES
STRENGTH CONCRETE CLASS (PROJECT)
DURABILITY IMPERMEABILITY + EXPECTED SERVICE LIFE
15
COMBINED ATTACKS
Example: Sea water effect
(Physical+Mechanical+Chemical+Biological effects)
Trigger effect of one attack over others
Mechanical Attack
Cracks
Chemical Attack
Increase in permeability
16
IN MOST CASES;
THE DIFFUSION OF WATER &/OR HARMFULL CHEMICALS &/OR GASES ARE NECESSARY FACTORS FOR CONCRETE DETERIORATION
17
DIFFUSION
PERMABILITY of CONCRETE
DURABILITY
18
19
Why durability problems? • Concrete − Hydrated Cement Phase (HCP) − Aggregate phase − Interstitial Transition Zone (ITZ) • Gel pores, Capillary pores, Air voids • Permeability and porosity • Aggressive species − Moisture, Sulphates, Chlorides, Carbon dioxide, Oxygen, Alkalies etc.
20
CEMENT
COMPLEX COMPOUNDS OF CEMENT
EARLY AGE STRENGTH
LATE & STEADY STRENGTH DEVELOPMENT
DURABILITY PROBLEMS (SULFATE ATTACK)
LOW HEAT OF HYDRATION
HYDRATION OF C3S AND C2S
TOBERMORITE
21
Influence of compound composition on properties of cement
Development of strength of
pure compounds according to
Bogue
Compound composition limits for
cements of ASTM C150
22
PERMEABILITY of CEMENT PASTE
MAJOR FACTOR PERMEABILITY
of CONCRETE PERMEABILITY of CEMENT PASTE
WATER IN
WATER OUT
Aggregate (no
pores)
Cement paste (porous nature)
23
24
PORE STRUCTURE of CEMENT PASTE
CAPILLARY PORES
GEL PORES
GEL PARTICLES CSH + CAH, etc. HYDRATED COMPONENTS + Ca(OH)2 + UNHYDRATED CEMENT + PORES.
25
PORE STRUCTURE of CEMENT PASTE
Calcium silicate hydrate gel
26
PORE STRUCTURE of CEMENT PASTE
27
PORE STRUCTURE of CEMENT PASTE
Crytals of Ca(OH)2 CSH (W/C=0.6, 5 days curing at
24ºC)
28
PORE STRUCTURE of CEMENT PASTE
Ca(OH)2
29
PORE STRUCTURE of CEMENT PASTE
Hexagonal Crystal Structure of Monosulfate Hydrate & Ettringite
30
PORE STRUCTURE of CEMENT PASTE
Ettringite (C3A.3CaSO4.32H2O).
31
PORE STRUCTURE of CEMENT PASTE
Ettringite
32
PORE STRUCTURE of CEMENT PASTE
Ettringite
33
PORE STRUCTURE of CEMENT PASTE
Monosulfate (C3A.CaSO4.12H2O).
34
PORE STRUCTURE of CEMENT PASTE
Thaumasite & Ettringite solid solution
35
PORE STRUCTURE of CEMENT PASTE
Thaumasite
(CaSiO3.CaCO3.CaSO4.15H2O).
36
37
PORE DISTRIBUTION of CEMENT PASTE
•COMPACTION
PORES
•ENTRAINED AIR
•CAPILLARY PORES
•GEL PORES
38
39
PORE DISTRIBUTION of CEMENT PASTE
•COMPACTION
PORES
•ENTRAINED AIR
•CAPILLARY PORES
•GEL PORES
10-
10
Effective on
Durability
Gel Pores
Capillary Pores
Entrained air
Compaction Pores
10-8
10-6
10-4
10-2
40
PORE DISTRIBUTION of CEMENT PASTE
•COMPACTION
PORES
•ENTRAINED AIR
•CAPILLARY PORES
•GEL PORES
10-
10
Gel Pores
Capillary Pores
10-8
10-6
10-4
10-2
Effective on
Durability
Entrained air
Compaction Pores
41
PORE DISTRIBUTION of CEMENT PASTE
•COMPACTION
PORES
•ENTRAINED AIR
•CAPILLARY PORES
•GEL PORES
10-
10
Capillary Pores
Entrained Air
10-8
10-6
10-4
10-2
Effective on
Durability
Gel Pores
Compaction Pores
42
PORE DISTRIBUTION of CEMENT PASTE
•COMPACTION
PORES
•ENTRAINED AIR
•CAPILLARY PORES
•GEL PORES
10-
10
Compaction Pores
10-8
10-6
10-4
10-2
Effective on
Durability
Gel Pores
Entrained air
Capillary Pores
43
PERMEABILITY of CEMENT PASTE
QUANTITY DURABILITY,
APPEARANCE,
HEALTHY
ENVIRONMENT
GEL PORES: (~28% of CEMENT PASTE, (15-20 A°
DIAMETER, DIAMETER OF WATER MOLECULES)
NOT DANGEROUS
CAPILLARY PORES: (~ 0-40% of CEMENT PASTE,
INTERCONNECTED WEB TYPE of DISTRIBUTION, ~1.3 DIAMETER)
DANGEROUS
TYPE, DIAMETER (CLOSED, CONNECTED, CAPILLARY ETC.)
DISTRIBUTION
CRACKS
PERMEABILITY OF CONCRETE
Permeability is important because:
1. The penetration of some aggresive solution may result in leaching out of Ca(OH)2 which adversely affects the durability of concrete.
2. In R/C ingress of moisture of air into concrete causes corrosion of reinforcement and results in the volume expansion of steel bars, consequently causing cracks & spalling of concrete cover.
3. The moisture penetration depends on permeability & if concrete becomes saturated it is more liable to frost-action.
4. In some structural members permeability itself is of importance, such as, dams, water retaining tanks.
PERMEABILITY OF CONCRETE
The permeability of concrete is controlled by capillary pores. The permeability depends mostly on w/c, age, degree of hydration.
In general the higher the strength of cement paste, the higher is the durability & the lower is the permeability.
46
DEVELOPMENT of HYDRATION
60 ml Water
% 0 Hydration
% 50 Hydration
% 100 Hydration
40 ml Cement
3.7 ml empty capillary pores
33.5 ml Capillary water
12.0 ml Gel water
30.8 ml Solid products of
hydration
20.0 ml unhydrated
cement
Hydrated cement
7.4 ml empty capillary pores
7.0ml Capillary water
24.0 ml Gel water
61.6 ml Solid products of hydration
Hydrated cement
42.8% Hydrated cement
85.6%
47
DEVELOPMENT of HYDRATION
Free water
48
HYDRATION OF CEMENT COMPONENTS
49
HYDRATION OF CEMENT COMPONENTS
50
MATURITY of HYDRATION DEPENDENT on W/C RATIO
ALLOWABLE min. VALUE of PERMEABILITY (USA BUREAU OF RECLAMATION WORK)
1.510-11 m/s THIS VALUE MAY CHANGE UP TO 1000 TIMES!
0.40 3 DAYS 0.45 7 DAYS 0.50 14 DAYS
0.60 6 MONTHS 0.70 1 YEAR
W/C App. Age required to produce maturity at which capillaries become segmented
>0.70 IMPOSSIBLE
51
DEPTH of HYDRATION
AVERAGE DIAMETER D = 30
UNHYDRATED CEMENT PARTICLE
HYDRATED PART (HARD)
UNHYDRATED PART (SOFT)
5.2
DEPTH of HYDRATION 5.2 after 3 months
WATER
time
52
HYDRATION RATIO of PURE COMPOUNDS OF CEMENT
0.2
0.4
0.6
0.8
1.0
C4AF
C3A
C3S
C2S
1 10 100 180 0
53
COEFFICIENT of PERMEABILITY
20
40
60
120
140
0.2 0.3 0
0.4 0.6 0.5 0.7 0.8
100
80
54
Change of Coefficient of permeability with curing time
days Coefficient of permeability (m/s)
Fresh 2 x 10-6
5 4 x 10-10 6 1 x 10-10
8 4 x 10-11
13 5 x 10-12
24 1 x 10-12
Final 6 x 10-13
Water/cement : 0.70 cement paste
55
APPARATUS FOR MEASURING PERMEABILITY
Water (under pressure)
Specimen
56
57
TRANSPORT MECHANISM OF WATER INTO CONCRETE
Water adsorption of the surface
Pore surface
Water vapour
( a)
Capillary condensation
( b) Splash
water
wetting
Time
Slow Fast
drying
wetting
100
Free surfaces of solids exhibit a surplus energy (surface energy) due to a
lack of binding components to the adjacent molecules.
In cement paste pores,
this surface energy absorbs water vapour
molecules onto the surface
Rela
tive h
um
idty
of
concre
te s
urf
ace
58
59
TRANSPORT MECHANISM OF WATER INTO CONCRETE
(c)
1
3 4
2 Concret
e
1 3
4
2
(b)
Concrete
Immersed Structure
Concrete
1
3
4
2
(a) Capillary Suction
Evaporation Efflorence
1. The transportation of water by capillary suction of hydrostatic pressure
2. The leaking of water and the agressive ions within the water
3. The evaporation or leaving of water from the structure
4. The deposition of aggressive materials and crystalization
60
CONCRETE CRACKS
61
62
CONCRETE CRACKS
FORMATION OF CRACKS IN CONCRETE IS NOT A RARE CASE.
CRACKS ARE FORMED DUE TO DIFFERENT CAUSES & HAVE TYPICAL
CHARACTERISTICS .
THERE IS A TENSILE STRESS PERPENDICULAR TO
THE DIRECTION OF CRACK.
STRESS FORMS DUE TO THE RESTRAINT OF DEFORMATIONS.
63
TYPES & FORMATION of CRACKS
EARLY FROST DAMAGE
FRESH STATE PLASTIC SHRINKAGE
SHRINKAGE
SETTLEMENT CONSTRUCTURAL MOVEMENTS
EARLY STRIPPING OF FORMS
BASE SETTLEMENT
HARDENED STATE
PHYSICAL
SHRINKABLE AGGREGATES
DRYING SHRINKAGE
BLEEDING
CHEMICAL BIOLOGICAL
CORROSION of REINFORCEMENT
ALKALI-SILICA REACTION
ACID ATTACK
SULFATE ATTACK
THERMAL
FREEZING & THAWING
TEMPERATURE DIFFERENCES
EARLY TERMAL SHRINKAGE EXT.
INT.
CONSTRUCTURAL (MECHANICAL)
EXCESSIVE LOADING
CREEP
INAPPROPRIATE DESIGN SETTLEMENT OF SUPPORT
CARBONATION DEF
64
Bending Cracks
A A J
I I I
C
K
C
E
F
Rust stains
B
L
M
N
N I
I
D
D
I
H
H
G
G
Cold dilations
C
O
O
O
O
O
Relative Shrinkage craks
Relative shrinkage craks
Late, ineffective dilations
Cold dilation
s
Shear crack
Bonding cracks
K
B
Bending crack
C
G
65
FORMATION of CRACKS & TIMES
Loading, service
conditions Alkali-
Aggregate Reaction
Corrosion
Drying Shrinkage
Early thermal Shrinkage
Plastic Shrinkage
Plastic Settlement
1 hour 1 day 1 week 1
month 1 year 50 years
1 hour 1 day 1 week 1
month 1 year 50 years
66
13.3 CRACK CONTROL
Cracks that may cause corrosion or may influence the apperance of structures should not be permitted.
max 0.4 mm Normal environment, indoors
0.3 mm Normal environment,
outdoors & Humid indoors
0.2 mm Humid environment, outdoors
0.1 mm Aggressive environment,
indoors & outdoors
TS500 /FEBRUARY 2000
TYPES & FORMATION of CRACKS
67
DISADVANTAGES of SHRINKAGE:
2. FORMATION of EXTRA STRESSES IN REINFORCEMENT
SHRINKAGE CRACKS
1. FORMATION of CRACKS
HAZARDS of CRACKS • DECREASE TENSILE STRENGTH
• WITH THE EASIER INGRESS of WATER
• FREEZE-THAW RESISTANCE
• DURABILITY AGAINST CHEMICAL ATTACKS
RESTRAINMENT of SHRINKAGE DEFORMATIONS CAUSE CRACKS.
DECREASES!
68
•HYDRAULIC SHRINKAGE
TYPES OF SHRINKAGE
•THERMAL SHRINKAGE LOSS of PORE WATER
DIFFERENCE of TEMPERATURE – IMPORTANT in MASS CONCRETE
•INSTRICT SHRINKAGE REDUCTION in VOLUME DUE to HYDRATION of CEMENT
•PLASTIC SHRINKAGE BLEEDING < EVAPORATION
•CARBONATION SHRINKAGE
EVAPORATION of WATER in CHEMICAL REACTION
3Ca(OH)2+CO2 CaCO3+H2O
69
•INTERNAL EFFECTS
FACTORS THAT INFLUENCE SHRINKAGE
CHEMICAL COMPOSITION (CaO, MgO & SO3)
CEMENT DOSAGE
HEAT of HYDRATION
QUANTITY of MIXING WATER
MODULUS of ELASTICITY of AGGREGATE
•EXTERNAL EFFECTS
LOW HUMIDITY
SPEED of WIND
HIGH TEMPERATURES
70
•DESIGN DETAILS
FACTORS THAT INFLUENCE SHRINKAGE
AREA/VOLUME RATIO of STRUCTURAL ELEMENTS
V1 = V2
Eva1 < Eva2
71
•DESIGN DETAILS
FACTORS THAT INFLUENCE SHRINKAGE
AREA/VOLUME RATIO of STRUCTURAL ELEMENTS
PERCENTAGE of REINFORCEMENT
UNIFORMITY of REINFORCEMENT PLACEMENT
UNPROPER CONSTRUCTION JOINTS
F1 = F2
RIGHT WRONG
72
•MIX DESIGN
PREVENTIVE MEASURES for SHRINKAGE CRACKS
•OPTIMUM AMOUNT of CEMENT
•MINIMUM AMOUNT of MIXING WATER
•MAXIMUM AMOUNT of COARSE AGGREGATE (GOOD QUALITY)
•CEMENT MINIMUM SHRINKAGE, LOW HEAT of HYDRATION, NOT TOO FINE.
•GOOD CURING
•DESIGN DETAILS SUFFICIENT AMOUNT of REINFORCEMENT,
UNIFORM PLACING
•INCORPORATION of FIBERS ( 0.6 – 0.9 kg/m3 )
73
74
SETTLEMENT CRACKS
Main Causes:
Poor grading, too much mixing water,
unsufficient compaction,
Water & cement mortar
Before Settlement
Reinforcement
After Settlement
Cracks
Coarse aggregate
75
A
PLASTIC SETTLEMENT CRACKS
Subdivision : Over Reinforcement – Deep Sections
Causes: Excess Bleeding – Rapid early drying conditions
Remedy : Reduce bleeding (air entrainment) or revibrate
76
A
B
B
PLASTIC SETTLEMENT CRACKS
Subdivision : Arching – Top of columns
Causes: Excess Bleeding – Rapid early drying conditions
Remedy : Reduce bleeding (air entrainment) or revibrate
77
A
B
B
C
PLASTIC SETTLEMENT CRACKS
Subdivision : Change of depth – Trough & waffle slabs
Causes: Excess Bleeding – Rapid early drying conditions
Remedy : Reduce bleeding (air entrainment) or revibrate
78
SETTLEMENT CRACKS
79
PLASTIC SETTLEMENT CRACKS
80
81
CAUSE:
EVAPORATION > BLEEDING RATE
DRYING OF TOP SURFACES
Evaporation
Bleeding
PLASTIC SHRINKAGE CRACKS
BLEEDING
Bleeding is the tendency of water to rise to the surface of freshly placed concrete.
It is caused by the inability of solid constituents of the mix to hold all of the mixing water as they settle down.
A special case of segregation.
BLEEDING
Undesirable effects of bleeding are: • With the movement of water towards the top, the top
portion becomes weak & porous (high w/c). Thus the resistance of concrete to freezing-thawing decreases.
• Water rising to the surface carry fine particles of cement which weaken the top portion and form laitance. This portion is not resistant to abrasion.
• Water may accumulate under the coarse agg. and reinforcement. These large voids under the particles may lead to weak zones and reduce the bond between paste and agg. or paste and reinforcement.
BLEEDING
The tendency of concrete to bleeding depends largely on properties of cement. It is decreased by:
Increasing the fineness of cement
Increasing the rate of hydration (C3S, C3A and alkalies)
Adding pozzolans
Reducing water content
Free Shrinkage, causes volume change, but no stresses
before shrinkage After Shrinkage
Restrained Shrinkage- creates stresses, which may cause cracking
Restrained shrinkage cracking Parallel cracking perpendicular
to the direction of shrinkage
Bleeding and its control Creates problems:
poor pumpability
delays in finishing
high w/c at the top
poor bond between two layers
u causes
u lack of fines
u too much water content
u Remedies
u more fines
u adjust grading
u entrained air
u reduce water content
Causes of Plastic Shrinkage Cracking
water evaporates faster than it can reach the top surface
drying while plastic
cracking
Plastic Shrinkage Cracking-Remedies Control the wind velocity
reduce the concrete’s temperature
use ice as mixing water
increase the humidity at the surface
fogging
cover w/polyethylene
curing compound
Fiber reinforcement
Curing The time needed for the chemical reaction of portland
cement with water.
Glue is being made.
concrete after 14 days of curing has completed only 40% of its potential.
70 % at 28 days.
Curing tips water
do not let it dry
dry concrete = dead concrete, all reactions stop
can not revitalize concrete after it dries
keep temperature at a moderate level
concrete with pozzolans, fly ash requires longer curing
Temperature effects on curing The higher the temperature the faster the curing
best temperature is room temperature
strongest concrete is made at temperature around 40 F.(not practical)
If concrete freezes during the first 24 hrs., it may never be able to attain its original properties.
Temperature effects on curing real high temperatures above 120 F can cause serious damage
since cement may set too fast.
accelerated curing procedures produce strong concrete, but durability might suffer.
autoclave curing.
95
PLASTIC SHRINKAGE CRACKS
D
Subdivision : Diagonal – Roads & Slabs
Causes: Rapid early drying – Low rate of bleeding
Remedy : Improve early curing
96
PLASTIC SHRINKAGE CRACKS
D
E
Subdivision : Random – Reinforced concrete slaps
Causes: Rapid early drying – Low rate of bleeding
Remedy : Improve early curing
97
D
E
F
PLASTIC SHRINKAGE CRACKS
Subdivision : Over reinforcement – Reinforced concrete slaps
Causes: Rapid early drying – Steel near surface
Remedy : Improve early curing
98
PLASTIC SHRINKAGE CRACKS
99
PLASTIC SHRINKAGE CRACKS
100
PLASTIC SHRINKAGE CRACKS
101
EARLY THERMAL CONTRACTION
G
Subdivision : External restraint – Thick walls
Causes: Excess heat generation – Rapid cooling
Remedy : Reduce heat &/or insulate
102
EARLY THERMAL CONTRACTION
G
H
Subdivision : Internal restraint – Thick slabs
Causes: Excess temperature – Rapid cooling
Remedy : Reduce heat &/or insulate
103
LONG TERM DRYING SHRINKAGE
I
I
Subdivision : Thin Slabs (and walls)
Causes: Insufficient joints – Excess shrinkage, inefficient curing
Remedy : Reduce water content, improve curing
104
LONG TERM DRYING SHRINKAGE
Insufficient (late) joints
105
SPALLING (crazing)
J
Subdivision : Against formwork – “fair-faced” concrete
Causes: Impermeable formwork- Rich mixes, poor curing
Remedy : Improve curing & Finishing
106
SPALLING (crazing)
J
K
Subdivision : Floated concrete - Slabs
Causes: Over-trowelling - Rich mixes, poor curing
Remedy : Improve curing & Finishing
CRAZING CRACKS
Crazing (Surface cracks develop)
CRAZING PLASTER CRACKS
109
CORROSION of REINFORCEMENT
110
CORROSION of REINFORCEMENT
111
L
Rust Stains
CORROSION of REINFORCEMENT
Subdivision : Natural – Columns & Beams
Causes: Lack of cover – Poor quality concrete
Remedy : Eliminate causes listed
112
L
M
CORROSION of REINFORCEMENT
Subdivision : Calcium chloride – Precast concrete
Causes: Excess calcium chloride – Poor quality concrete
Remedy : Eliminate causes listed
113
CORROSION of REINFORCEMENT
114
CORROSION of REINFORCEMENT
115
CORROSION of REINFORCEMENT
Electrical pillars with corrosion damage in İZMİR
116
ALKALI-AGGREGATE REACTION
N
Subdivision : Damp locations
Causes: Reactive aggregate plus high-alkali cement
Remedy : Eliminate causes listed
117
ALKALI-AGGREGATE REACTION
118
ASR
119
ASR
120
ALKALİ-AGREGA REAKTİVİTESİ
ALKALİ-KARBONAT REAKTİVİTESİ BOZULMASI
ACR
121
DEF (DELAYED ETTRINGITE FORMATION)
122
THAUMASITE FORMATION
Swiss tunnel structures: concrete damage by formation of thaumasite (Romer vd. 2003)
123
LOADING CRACKS
PURE BENDING
PURE TENSION
124
LOADING CRACKS
TORSION
Bending
Bond Cracks
CONCENTRATED
LOAD
SHEAR
125
LOADING CRACKS
SHEAR
126
LOADING CRACKS
SETTLEMENT CRACKS
Settlement of Support
Cracks
127
DURABILITY of CONCRETE
STRUCTURES
Prof. Dr. Halit YAZICI
Part- I
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