DURABILITY of CONCRETE STRUCTURES PART...
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DURABILITY of CONCRETE STRUCTURES PART 4 Prof. Dr. Halit YAZICI
Transcript of DURABILITY of CONCRETE STRUCTURES PART...
DURABILITY of CONCRETE STRUCTURES
PART 4
Prof. Dr. Halit YAZICI
PHYSICAL & MECHANICAL (freeze-thaw, waves, erosion, salt crystallization)
CHEMICAL Sulfate (Mg2SO4)
BIOLOGICAL (positive&negative effects)
MARINE ENVIRONMENT
PHYSICAL & MECHANICAL (freeze-thaw, waves, erosion, salt crystallization)
CHEMICAL Sulfate (Mg2SO4)
BIOLOGICAL (positive&negative effects)
PHYSICAL & MECHANICAL (freeze-thaw, waves, erosion, salt crystallization)
CHEMICAL Sulfate (Mg2SO4)
RF CORROSION
SPLASH ZONE
TIDAL ZONE
SUB-SURFACE
ZONE
SEA BASE
COASTAL ATMOSPHERIC ZONE
WINDS CARRYING SALTY WATER
Structures close to Shores
RISING
LOWERING
Cracks Due to Steel Rusting Cracks Due to Freeze-Thaw, Wetting-Drying
Chemical effects: CO2 effect Sulfate attack Mg ions exchange
Decomposition of hydrated cement paste due to chemical processes
Erosion by waves (Sand, gravel, ice, etc.
COASTAL ATMOSPHERE
TIDAL ZONE
BELOW SEA LEVEL
HIGH
LOW
CONCRETE
STEEL
BIO
LO
GIC
AL F
OR
MA
TIO
NS
MARINE ENVIRONMENT
SEA WATER:
MOST IMPORTANT CHLORIDE SOURCE
CORROSION :
MAJOR RISK FACTOR OF COASTAL
REINFORCED CONCRETE STRUCTURES
WRONG DESIGN & PRODUCTION
LEADS TO HEAVY DAMAGE IN A
SHORT PERIOD (5-10 YEARS)
SEA ENVIRONMENT
DETERIORATION RISKS
Physical & Chemical Processes
RISKS ACCORDING TO ZONES Submerged zones
Tidal zone
Splashing zone
Coastal Atmospher
e Chloride Corrosion High High High Low
Erosion (waves, floating materials) None High High Low
Drying – Wetting (Salt
Crystallization)
Low High High None
Freeze - Thaw Low High High Low
Chemical Reaction Low Low High High
Biological Formations None High High High
SALINITY & ION CONCENTRATION OF TURKISH SEAS
Sea Region Total
Salinity (%)
Mg+2
(mg/l)
SO4+2
(mg/l)
Cl-
(mg/l)
Na+
(mg/l)
Ca+2
(mg/l)
Black sea Zonguldak 1.7 630 1270 8400 5260 250
Marmara Erdek 2.6 960 1940 12840 8050 380
Aegean Ayvalık 3.8 1400 2830 18770 11770 560
Mediterranean Bodrum 3.9 1440 2900 19270 12080 580
SEA ENVIRONMENT
Excessive deterioration in wetting-drying zone
SEA ENVIRONMENT
YARIMCA PETKIM SEA PLATFORM (after earthquake)
SEA ENVIRONMENT Excessive deterioration in wetting-drying zone
SEA ENVIRONMENT
CLASSIFICATION OF ENVIRONMENTAL EXPOSURE –TS EN206
XD1 : HUMID, RARELY DRY (Splashing of water containing Chloride ions)
XD2 : MODERATE HUMIDITY (Swimming pools, industrial water)
XD3 : CONTINUOUSLY DRY-WET ENVIRONMENT (Bridges, Floors, car parking structures)
0.55 Max.
W/C 0.55 0.45
PRECAUTIONS DUE TO CHLORIDE
CORROSION (EXCEPT SEA WATER)
XD1 XD2 XD3
Min.
STRENGTH C30 C30 C35
Min. CEMENT
DOSAGE
(kg/m3)
300 300 320
CLASSIFICATION OF ENVIRONMENTAL EXPOSURE –TS EN206
XS1 : INDIRECT CONTACT with SEA WATER (Structures close to shores)
XS2 : SUBMERGED STRUCTURES (Special zones of coastal structures)
XS3 : COMPONENTS of COASTAL STRUCTURES EXPOSED TO TIDAL WAVES & SPLASHES
0.50 Max.
W/C 0.45 0.45
PRECAUTIONS AGAINST SEA-WATER ATTACK XS1 XS2 XS3
Min.
STRENGTH C30 C35 C35
Min. CEMENT
DOSAGE
(kg/m3)
300 320 340
CLASSIFICATION OF
ENVIRONMENTAL EXPOSURE
CLASSIFICATION OF ENVIRONMENTAL EXPOSURE –TS EN206
FREEZE-THAW EFFECT XF1 XF2 XF3 XF4
Max. W/C
0.55 0.55 0.50 0.45
XF1 : MODERATELY WATER SATURATED (Vertical Concrete Surfaces)
Min. Strength (MPa)
C30 C25 C30 C30 Min. CEMENT
DOSAGE (kg/m3) 300 300 320 340
Min. Entrained Air (%)
--- 4.0 4.0 4.0
OTHER FREEZE-THAW RESISTANT AGGREGATE
XF2 : MODERATELY WATER SATURATED, DE-ICING AGENTS (Vertical Concrete Surfaces)
XF3 : HIGHLY WATER SATURATED (Horizontal Concrete Surfaces)
XF4 : HIGHLY WATER SATURATED, DE-ICING AGENTS (Horizontal Concrete Surfaces)
CLASSIFICATION OF ENVIRONMENTAL EXPOSURE –TS EN206
AGGRESSIVE CHEMICAL
ENVIRONMENT XA1 XA2 XA3
Max. W/C
0.55 0.50 0.45
XA1 : LOW AGGRESIVE CHEMICAL ATTACK
Min. Strength (MPa)
C30 C30 C35 Min. CEMENT
DOSAGE (kg/m3) 300 320 360
OTHER SULFATE RESISTANT CEMENT
XA2 : MODERATE AGGRESSIVE CHEMICAL ATTACK OR SEA WATER
XA3 : EXCESSIVE AGGRESSIVE CHEMICAL ATTACK
CLASSIFICATION OF ENVIRONMENTAL EXPOSURE –TS EN206
XD1 : HUMID, RARELY DRY (Splashing of water containing Chloride ions)
XD2 : MODERATE HUMIDITY (Swimming pools, industrial water)
XD3 : CONTINUOUSLY DRY-WET ENVIRONMENT (Bridges, Floors, car parking structures)
0.55 Max.
W/C 0.55 0.45
PRECAUTIONS DUE TO CHLORIDE
CORROSION (EXCEPT SEA WATER)
XD1 XD2 XD3
Min.
STRENGTH C30 C30 C35
Min. CEMENT
DOSAGE
(kg/m3)
300 300 320
GENERAL PRECAUTIONS
MILD ATTACK
1) TO PRODUCE IMPERMEABLE CONCRETE
- Proper Gradation
- Stabilization of free Ca(OH)2 with pozzolans
- Appropriate compaction
- Low W/C ratio
- Appropriate Curing
- No Cracks
- Structural Design
- Water-Proofing admixtures
GENERAL PRECAUTIONS
- Impermeable concrete cover with sufficient thickness
CONCRETE COVER
CORROSION DUE TO
CARBONATION
NO RISK
XC1 XC2/XC3 XC4 X0 XD1/XD2/XD3 XS1/XS2/XS3
CORROSION DUE TO
CHLORIDES
CORROSION DUE TO
SEA WATER
REINFORCED
CONCRETE
Cmin (mm)
15 25 30 10 45 45
PRESTRESSE
D CONCRETE
Cmin (mm)
25 35 40 20 55 55
prEN1992-1
CONCRETE COVER(mm)
I : PROTECTED SURFACES AGAINST AGGRESSIVE ENVIRONMENT
20 35
---- ---- ---- 0.60 35 300
20 30 40 50
---- 0.55 40 325
20 25 30 40 60
0.50 45 350
20 20 25 30 50
0.45 50 400
I
II
III
IV
V
MAX W/C
CONCRETE STRENGTH
MIN CEMENT DOSAGE
25 ---- ---- ---- ---- 0.65 30 275
III : EXPOSED TO EXCESSIVE RAIN, DRYING & WETTING
II : PROTECTED SURFACES EXCESSIVE RAIN & FROST DAMAGE, EXISTANCE OF CONDENSATION
IV : SEA WATER, DE-ICING AGENT, FREEZE-THAWING
V : ACIDIC WATER (pH4.5), WEARING, EROSION
- Structural Design
H2O H2O H2O Isolation
Protected Steel
H2O H2O H2O H2O
WRONG RIGHT PARTIALLY RIGHT
WRONG RIGHT
PRECAUTIONS
- Structural Design
PIPE
COLUMN
WRONG
RAIN WATER
WRONG
ACCUMULATION OF
AGGRESSIVE MATERIALS
EVAPORATION
PRECAUTIONS
- Structural Design
PRECAUTIONS
WRONG WRONG
RIGHT RIGHT RIGHT
- Structural Design
PRECAUTIONS
Severe Attack
Reinforced Concrete bridge
Insulated (de-icing agents)
No-insulation
Solution: Good drainage Good insulation Good Maintanence
- Structural Design
PRECAUTIONS
WRONG
Accumulation of rain water
Splash
RIGHT
Soil
Garden
- Structural Design
PRECAUTIONS
Rain water drainage
WATER FROM RAIN, PLANT WATERING, UNDERGROUND WATER
No-insulation
CAPILLARY SUCTION
- Structural Design
PRECAUTIONS
WRONG
WRONG
RIGHT
INSTALLATION HOLES & PIPES
RISK OF:
- BLOCKING
- FREEZE-THAW
- CHEMICAL REACTIONS
- AGGRESSIVE MAT. (Cl- etc.) ACCUMULATION
DRAINAGE IS NEEDED
- Structural Design
PRECAUTIONS
Air pollution, dust deposition
Laminar Air stream
Air pollution, dust deposition
Heavy air stream
- Structural Design
PRECAUTIONS
Discoloring , deposition of dust
Flow & washing out effect of rain
- EXAMPLES OF POOR DESIGN
PRECAUTIONS
- EXAMPLES OF POOR DESIGN
PRECAUTIONS
- PROPER DESIGN
PRECAUTIONS
2) (1) + USAGE OF SPECIAL CEMENTS
- PC, EARLY HIGH STRENGTH
- SLAG CEMENTS OR CEMENTS WITH LOW
HYDRATION HEAT VALUES
- TRASS CEMENTS
- SULFATE RESISTANT CEMENTS
- SUPER SULFATED CEMENTS - ALUMINA CEMENTS
PROVIDED: OTHER FACTORS SAME!
CURING PERIOD IS IMPORTANT!
MODERATE EFFECT
PRECAUTIONS IN
CR
EA
SE
IN
D
UR
AB
ILIT
Y
NATURAL POZZOLANS
SLAGS FLY-ASHES
ETC.
BLENDED CEMENTS
CURING IS MORE IMPORTANT THAN PORTLAND CEMENTS
LOW HYDRATION RATE
PORTLAND CEMENT
HIGH BLENDED CEMENT 0 MINERAL
ADMIXTURE %
PERMEABILITY INSUFFICIENT CURING
GOOD CURING
3) (2) + INSULATION OF SURFACES
SEVERE ATTACK
PRECAUTIONS
SEVERE ATTACKS
APPLICATION OF
POLYMER BASED
IMPERMEABILITY PAINTS
LIMITED PROTECTION
RE-APPLICATION NECESSARY
IN SHORT TIME PERIODS
PRECAUTIONS
CONCRETE
STRUCTURE
SURFACE
TREATMENT
HARDENING
UP TO 6 mm
DEPTH
INSULATION
MATERIAL CONTACT
PLANE
UNDERGROUND WATER
SOIL
WATER PROOF
MEMBRANE
FOUNDATION
CONCRETE
(LEAN)
SEVERE ATTACK
TO PROVIDE WATER
PROOF BY PLASTIC
BASED INSULATION
MATERIALS
CONCRETE SURFACES
SHOULD BE CLEAN &
DRY. GOOD BOND IS
NECESSARY
INSULATION APPLICATIONS
DURABILITY of CONCRETE STRUCTURES
PART 4
Prof. Dr. Halit YAZICI
