DURABILITY of CONCRETE
STRUCTURES
Assist. Prof. Dr. Mert Yücel YARDIMCI
Part- IV Physical and Mechanical Factors
This presentation covers the subjects in CEB Durable Concrete Structures Guideline and has been prepared by the graduate students under the supervision of Prof.Dr.Bülent BARADAN in Dokuz Eylul University.
1
PHYSICAL & MECHANICAL FACTORS of CONCRETE DEGRADATION & CRACKS
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
2
WEARING, EROSION, CAVITATION
3
Abrasion (or ‘wear’) of concrete usually refers to the action of traffic (in the form of wheeled vehicles, foot traffic, etc.) on concrete surfaces, which can lead to the gradual loss of material, leading to the loss of a level surface and to a potentially heightened vulnerability to other durability-compromising processes.
Erosion refers to the loss of surface material as a result of either the action of solid particles being carried by moving water or a process known as ‘cavitation’.
4
DRY FRICTION EFFECT
TRAFFIC LOAD (TANKS&LOADERS, etc.) DRAG of HEAVY MATERIALS
ABRASIVE WEARING
MASS LOSS WITHIN TIME
WEARING of CONCRETE SURFACES by LIQUIDS
with SUSPENDED SOLIDS
EROSION
FLOW of WATER WITH HIGH VELOCITY
SUDDEN DROPS of PRESSURE,
IMPACT of WATER BUBBLES on
SURFACE
CAVITATION
WEARING, EROSION, CAVITATION
5
Mechanisms of abrasion
The same effect can be caused by skidding of a wheel or foot on a pavement or floor surface.
6
Mechanisms of abrasion
The action of traffic over a concrete surface generates stresses that can cause microcracking, ultimately leading to abrasion.
The relatively low strength of concrete in tension and shear makes these types of stress the largest threat to the integrity of a pavement or floor
The action of a human foot will produce similar stress distributions!
WEARING, EROSION, CAVITATION
WEAK SURFACE DUE TO HIGH W/C
Excessive troweling can cause a formation of dense surface that can be easily delaminate from the concrete!
7
8
CAVITATION HAZARDS on a SPILLWAY of a DAM
9
Concrete surfaces which are subjected to flowing water with very high velocity may be damaged by erosion (or cavitation). It is particularly seen in spillways of dams.
CAVITATION - EROSION
Cavitation damage to the concrete wall
of the 15.2m diameter Arizona spillway
at the Hoover Dam. The hole is 35m
long, 9m wide and 13.7m deep.
Cavitation damage on Karun dam, Iran 10
CAVITATION - EROSION
11
CAVITATION - EROSION
The rate of erosion • increases with the velocity of the flowing water. • increases with hardness of the particles carried by a
fluid. • decreases with the amount of particles in
suspension.
Cavitation may occur wherever there is a curve in the streamlines followed by the flow of water, on the inside of the curve.
12
Damage from individual cavitation events takes the form of small pits in the surface, but since the formation of bubbles will typically occur with great frequency, the cumulative effect can be significant.
CAVITATION - EROSION
The bubbles of water vapour violently collapse in a manner similar to that shown in Figure 2.59. This collapse produces a fast-moving jet of water that leads to the generation of significant local stresses.
13
Factors influencing resistance to abrasion and erosion
• W/C ratio of concrete
• Maximum aggregate size
• The strength of aggregate
• The amount of coarse aggregate
CONCRETE SURFACE AFTER WEARING TEST
CONCRETE SURFACE WEARED by STUDDED
TIRES
WEARING, EROSION, CAVITATION
14
PROPER GRADING
APPROPRIATE COMPACTION
LOW W/C RATIO
BETTER CURING
EFFECTIVE MEASURES in CONTROLLING
WEARING
SOME of THESE METHODS MAY BE IMPLEMENTED TOGETHER
PROPER SURFACE FINISHING
USING SURFACE HARDENERS CAUTION: ASR
15
In contrast with abrasion, a stronger concrete may not necessarily be effective in preventing damage due to cavitation. Causes of cavitation should be eliminated by the revision of the hydraulic design.
EFFECTIVE MEASURES in CONTROLLING
WEARING, EROSION, CAVITATION
Siliceous powder poured on slab should contain
no reactive silica
16
CLASSIFICATION OF ENVIRONMENTAL EXPOSURE –TS EN206
WEARING XM1 XM2 XM3
Max. W/C ratio 0.55 0.45 0.45
Min. Class of concrete C30/37 C30/37 C35/45
Min. amount of cement (kg/m3) 300 340 340
XM1 MODERATE
WEARING
EFFECT
Floors subjected to plastic-wheeled traffic or industrial floors with
surface hardeners
XM2 EXCESSIVE
WEARING
EFFECT
Floors subjected to plastic-wheeled or rubber tyred traffic, industrial
floors with surface hardeners
XM3 VERY
EXCESSIVE
WEARING
EFFECT
Floors subjected to steel or elastomer tyre-wheeled traffic and
impact, frequently use of tyre-chains, industrial floors with surface
hardeners, water structures vulnerable to erosion
17
FREEZE – THAW EFFECT
FRESH CONCRETE HARDENED CONCRETE
FREEZING of CAPILLARY WATER
SWELLING (~9%)
INTERNAL STRESSES
CRACKS
DAMAGE
FORMATION of PORES by SWELLING EFFECT of ICE
RETARDATION or DELAY of HYDRATION REACTION
(<-12C)
RE-INITATION of HYDRATION by MELTING of ICE
VERY POROUS STRUCTURE, DECREASE of DURABILITY & MECHANICAL PROPERTIES
NECESSITY of REMIXING FRESH-THAWED CONCRETE !!
18
FREEZE – THAW EFFECT
FROZEN CONCRETE AT FRESH STATE
19
20
Very porous concrete (Honey combed)
Impermeable concretes
Dry concretes
NOT AFFECTED by FREEZE&THAW!
3 FACTORS AFFECTING FREEZE-THAW RESISTANCE of CONCRETE :
• PORE STRUCTURE
• SATURATION of CONCRETE
• COMPRESSIVE STRENGTH (SUGGESTED VALUES 5-14 MPa !!!!!)
FREEZE – THAW EFFECT
INTERESTING CONTRASTS
21
PRECAUTIONS
22
SUPPLIER’S PRECAUTIONS
CONSUMER’S PRECAUTIONS
- TO PLACE CONCRETE AT WARMER PERIOD of DAY
- TO PRODUCE HIGH EARLY STRENGTH CONCRETE
a) TO USE a CEMENT WITH HIGH HYDRATION HEAT VALUE (FINE CEMENTS)
b) HIGHER CEMENT CONTENT, LOWER W/C RATIO
c) TO USE ACCELERATOR TYPE (ANTI FREEZING) ADMIXTURES (CaCl2 CONTENT MAX 1%)
d) STEAM CURING
e) IMPLEMENTATION OF VARIOUS METHODS SIMULTANEOUSLY
FREEZE & THAW HAZARD
23
Local pop-outs, Peelings, micro cracks in cement mortar matrix
Pop-outs due to insufficient aggregate usage (non-resistant to freezing&thawing)
FREEZE – THAW EFFECT
24
FREEZE – THAW EFFECT
25
UŞAK-EŞME
FREEZE – THAW EFFECT
26
FREEZE – THAW EFFECT
DENİZLİ, ÇAMELİ
REINFORCED RETAINING WALL 27
FREEZE – THAW EFFECT
DENİZLİ, AKDERE
REINFORCED GARDEN WALL 28
FREEZE – THAW EFFECT
DENİZLİ, IŞIKLI
REINFORCED CONCRETE SLAB 29
DENİZLİ, IŞIKLI
REINFORCED CONCRETE SLAB
FREEZE – THAW EFFECT
30
FREEZE – THAW EFFECT
31
COLD WEATHER CONCRETING
32
- TO PRODUCE AIR ENTRAINED CONCRETE
AIR-ENTRAINING AGENTS
(SODIUM ABIETATE, LIGNO SULFONATE, VEGETABLE OILS,
SYNTHETIC DETERGENTS)
AIR BUBBLES 10-250 DIAMETER
AIR BUBBLES 3109 ~ 7109/m3 2-9% of TOTAL VOLUME
PRECAUTIONS
33
- TO PRODUCE AIR ENTRAINED CONCRETE
AIR-ENTRAINING AGENTS
(SODIUM ABIETATE, LIGNO SULFONATE, VEGETABLE OILS,
SYNTHETIC DETERGENTS)
AIR BUBBLES 10-250 DIAMETER
AIR BUBBLES 3109 ~ 7109/m3 2-9% of TOTAL VOLUME
PRECAUTIONS
34
FREEZE & THAW HAZARD
35
Air-entrained concrete
Non-air entrained concrete
7000
5000
6000
4000
3000
2000
1000
0
W/C ratio
0.35 0.45 0.55 0.65 0.75 0.85 Num
ber
of
free
zing
-thaw
ing c
ycl
es
that
cau
ses
25%
of
wei
ght
loss
AIR ENTRAINING AGENTS
36
AFTER 140 FREEZE-THAW CYCLES
CEMENT DOSAGE 350 kg/m3
Entrained air
%4.6 %8.3
No strength loss in air entrained concrete
AIR ENTRAINING AGENTS
FREEZE-THAW CYCLES
37
Suggested air entrainment percentages
38
Maximum
aggregate
diameter (mm)
Total air content of concrete
Moderate
(Seldom effect of
humidity & de-icing agents)
Severe
(Continous effects of
humidity & de-icing agents)
9.5 6 7.5
12.5 5.5 7
19 5 6
25 5 6
37.5 5 5
Air void analyser aerometer
Fresh concrete
Hardened concrete
Variation of freezing point of water by pore diameter
39
Fre
ezin
g P
oin
t (
C)
micro
Pore radius (nm)
10
20
30
0 1 10 100
mesa macro
Saline water
Plain water
DE-ICING OPERATION
40
EFFECTS of DE-ICING OPERATION
41
DE-ICING OPERATION LOWERS THE FREEZING POINT of WATER
DURING THAWING of ICE; THERE WILL BE SUBSTANTIAL DROP in TEMPERATURE at THE CONCRETE SURFACE (THERMAL SHOCK)
Ten
sile
Str
ain (
c)
Concrete depth
TEMPERATURE DIFFERENCE BETWEEN SURFACE & INTERIOR of CONCRETE WILL CAUSE
INTERNAL STRESSES
EFFECTS of DE-ICING OPERATION
42
DE-ICING OPERATION CHANGE THE FREEZING BEHAVIOUR of PORE WATER
AS EXPLAINED BEFORE; FREEZING POINT of PORE WATER WILL BE LOWER WHEN THE PORE RADIUS IS SMALLER.
BOTH THE CHANGE in CONTENT of DE-ICING AGENTS & CHANGE in TEMPERATURE, MAY CAUSE FREEZING at
DIFFERENT TIME PERIODS FOR VARIOUS DEPTHS of CONCRETE LAYERS.
AND ALSO; THE CONTENT of DE-ICING AGENTS WILL DECREASE with INCREASING DISTANCE FROM THE SURFACE & with the DECREASING PORE RADIUS
SCALING MAY OCCUR
EFFECTS of DE-ICING OPERATION
43
IN CASE of CHLORIDES; (THE DE-ICING SALTS MOST FREQUENTLY APPLIED) THERE IS A SERIOUS RISK of
REINFORCEMENT CORROSION
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) 44
WETTING & DRYING
JOINT INTERSECTIONS
CRACKING DUE TO COMBINATION of wetting&drying and freezing&thawing
D CRACKS
45
HIGH TEMPERATURES
46
HIGH TEMPERATURES
47
HIGH TEMPERATURES
48
NO PROBLEM UP TO 1-2 HOURS & 250C !
100~150ºC EVAPORATION of CAPILLARY WATER
150~200ºC SHRINKAGE, FORMATION of MICRO CRACKS,
DECREASE of TENSILE STRENGTH
– PINKISH COLOR
~300ºC LOSS of HYDRATED WATER in AL.&FERROUS
COMPOUNDS, DECREASE of COMPRESSIVE
STRENGTH – DEEP PINK – REDDISH COLOR
~400ºC Ca(OH)2 CaO
30% VOLUME LOSS
(DURING FIRE FIGHTING OPERATIONS)
400~600ºC DESTRUCTION of CSH STRUCTURE
- GREY - WHITE COLOR
~60-80% of COMPRESSIVE STRENGTH LOSS
NO POISONOUS GASES, NO SMOKE OR FLAME !
LOSS of STRENGTH
49
400 300 200 100 20
120
100
80
60
40
20
0
Temperature (C)
Res
idu
al
Str
eng
th (
%)
Slow cooling
Cooling by water
LOSS of STRENGTH
50
400 300 200 100
120
100
80
60
40
20
0
Temperature (C)
Res
idu
al
Str
eng
th (
%)
500 600 700 800 900 1000 20
Limestone
Gravel
Color change
Pink or reddish Gray Ash
0
20
40
60
80
100
120
140
0 20 40 60
Res
idu
al c
om
per
essi
ve
stre
ng
th, %
…
……
……
..
FA (%)
300 °C
600 °C
900 °C
Aggregate: Pumice
W/C ratio:0,72
Air cooling
HIGH TEMPERATURE RESISTANT MORTAR
51
Res
idu
l co
mp
ress
ive
stre
ngth
, %
No strength loss at 900 ºC
LOSS of STRENGTH
52
STRUCTURAL STEEL
53
T – Temperature ( C )
Res
idual
Str
eng
th (%
)
40
20
60
80
100
0 100 200 300 400 500 600 700
St I (Yield Stress)
Cold formed StIIIb
(tensile strength)
High Strength St IIIa
(tensile strength)
Change of - behaviour of structural steel due to
high temp.
54
12
11
10
9
8
5
6
- Strain
-
Str
ess
(Mp
a)
400
300
200
100
500
600
700
0.02 0.00 0.04 0.06 0.08 0.10 0.12
1 : 24C 2 : 99C 3 : 149C 4 : 204C 5 : 260C 6 : 316C
7 : 368C 8 : 427C 9 : 482C 10 : 535C 11 : 593C 12 : 649C
4 7
3 1
1
2
2
Precautions
Use mineral admixtures (fly ash,
granulated blast furnace slag)
Use thermally stable aggregate
( limonite, basalt, barite, broken heat
resistant bricks, koronden, cromite
etc.)
Not silica fume
Use reinforcement with sufficient
concrete cover (min. 4 cm for good fire
resistance) 55
CHEMICAL & BIOLOGICAL FACTORS
-SULFATE ATTACK -DEF -ASR, 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
56
HYDROLYSIS & WASHING OUT
57
CH
CSH
CAH
pH 12.5-13.5
are STABLE
HYDROLYSIS & WASHING OUT
58
CH, CSH, CAH
are NOT
STABLE
WATER WITH
LOW pH
(pH<6.5)
pH
DROPS
HYDROLYSIS & WASHING OUT
59
CH, CSH, CAH
HYDROLYSIS
WASHED OUT
HYDROLYSIS & WASHING OUT
60
SOURCES OF LOW pH
UNDERGROUND WATER CONTAINING SULFATE &/or CHLORIDE
WATERS WITH LOW pH
INDUSTRIAL WASTE WATER
SEA WATER
WATER CONTAINING FREE CO2 &/or H+
DANGER LIMITS MILD pH = 5.5 - 4.5
SEVERE pH = 4.5 - 0.0
CONCRETE STRENGTH DECREASES 2%
with HYDROLYSIS & WASHING OUT of
1% Ca(OH)2 (Mehta,1997) 61
ACID ATTACK
62
Acid Solution from the environment
Removal of reaction
products by dissolution or
abrasion
Conversion of hardened cement
layer by layer: microstructure (pore system)
destroyed
Converted layer; if not removed, more permeable
than sound concrete
DISSOLUTION EFFECT OF WATER WITH pH<6.5 ON
CEMENT MORTAR & CARBONATE AGGREGATES
STRONG ACIDS
SULFURIC ACID H2SO4
HYDROCHLORIC ACID HCl
NITRIC ACID HNO3
WEAK ACIDS
H2S + WATER FILM + OXYGEN H2SO4
SO3 + WATER FILM + OXYGEN H2SO4
ACID ATTACK
63
CO2 + H2O H2CO3
CaO + CO2 CaCO3
From air
water
(CARBONIC ACID)
(MINERAL WATER)
H2CO3+ Ca(HCO3)2 (CALCIUM BICARBONATE)
Ca(HCO3)2 + Ca(OH)2 CaCO3 + 2 H2O
IF AMOUNT OF CO2 IS LIMITED,
THE REACTION WILL STOP AFTER A WHILE
CaCO3
ACID ATTACK
64
2NH4NO3+Ca(OH)2+2H2O
INDUSTRIAL MATERIAL & WASTES and POLLUTED
WATER MAY CONTAIN ORGANIC & INORGANIC
COMPOUNDS.
FERTILIZER PLANTS WASTES
(FROM AMMONIUM NITRATE FERTILIZATION)
3Ca(NO3)2.4H2O + 2NH3
3Ca(NO3)2.4H2O + 3CaO.Al2O3.6H2O
3CaO.Al2O3.Ca(NO3)2.10H2O
SEWAGE WATER
H2S + 2O2
Aeorobic bacteria H2SO4
ACID ATTACK
65
SEWER SYSTEM
Hydrogen sulphide formation in oxygen-free surface
Escape of hydrogen sulphide
Acid attack on concrete
Bacteriological formation of sulphuric acid in O2
containing environment at the concrete surface
ACID ATTACK
66
ACID ATTACK
67
(Typical new and
undeteriorated condition of
sewer pipe)
(Concrete deterioration
of sewer pipe)
Effect of various acids on Concrete
68
Rate of
Attack
Type of acid
Inorganic Organic
Medium Phosphoric Tannic
Rapid
Hydrofloric,
Hydrochloric,
Nitric, Sulfiric
Asetic,
formic,
lactic
Slow Carbonic -
Negligible - Oxalic, Tartaric
ACID ATTACK
MASS LOSS, STRENGTH LOSS
INCREASE IN PERMEABILITY
SPECIMENS SUBJECTED TO 7% SULFURIC ACID CONCENTRATIONS FOR 21 DAYS AFTER STANDARD CURING OF 28 DAYS
HNO3 HCl H2SO4 CH3COOH 69
ACID ATTACK
SURFACE VIEW OF SPECIMENS SUBJECTED TO DIFFERENT ACID TYPES AND CONCENTRATIONS
pH meter
70
ACID ATTACK
Concrete silo
Agriculture Industry
grain silos
Organic acid
attack
humidity 71
Concrete pits for pickle production
ACID ATTACK
72
Phosphoric-Acid-Industry
ACID ATTACK
Concrete silo
Rubber- and Brick-Lining
for a concrete Reactor in
the Filtration unit
73
ACID ATTACK
A mineral processing plant’s
neutralization system pits and
chambers with a throughput of
500,000 litres per hour. The process is
continuous (24 hours a day). Tropical
location, the effluent is never below
45° C.
Concrete pit
74
ACID ATTACK
Concrete olive pool
Oleic acid attack
Triglyceride esters of oleic acid
compose the majority of olive
oil, although there may be less
than 2.0% as actual free acid in
the virgin olive oil, with higher
concentrations making the olive
oil inedible. 75
Attack by feed acids (acetic lactic acid) and Urea
Concrete floors and columns at animal barns
ACID ATTACK
76
A fertilizer basement in construction for a cow barn
ACID ATTACK
77
Corrosion of floodgate
due to acidic water
ACID ATTACK
Reinforced concrete floodgates
78
Precautions against acid attack
Epoxy impregnated
concrete floor or
direct epoxy coating
Coating of concrete
surface with polimer
or bituminous based
materials
Impermeability is not a sufficient precaution method against acid attack
79
SULFATE ATTACK
80
DRY & SOLID SALTS NOT DANGEROUS! HUMID ENVIRONMENTDANGEROUS
Diffusion of sulfates into
concrete
Sulfate solution from the
environment
Expansion reaction of
C3A
Hydrated C3A
Crack formation
SOURCES OF SULFATE
SOIL (WHITE SALT RESIDUALS ON SURFACE; LAND DRY & WITHOUT TREES & PLANTS EXCEPT SOME BUSHES)
CEMENT (FROM GYPSUM CaSO4.2H2O, max. SO3 3%)
SEA WATER, UNDERGROUND WATER
SULFATE ATTACK
81
General view of sulfated soils
82
Mortar samples exposed to sulfate
83
BEFORE SULFATE
EXPOSURE
AFTER SULFATE ATTACK
SULFATE REACTIONS
84
IONS OF SO3> 200 (600 ppm) mg/l DANGEROUS
Sulfate ions
SO3- + Ca(OH)2 + H2O CaSO4.2H2O (124% Volume increase)
Gypsum
Na2SO4
Na2SO4.10H2O + Ca(OH)2 CaSO4.2H2O + 2NaOH + 8.H2O
Gypsum
MgSO4
MgSO4.7H2O + Ca(OH)2 CaSO4.2H2O+Mg(OH)2 + 5.H2O
Gypsum
REACTIONS WITH Ca(OH)2
3(CaSO4.2H2O)+3 CaO.Al2O3.12H2O+20H2O
3CaO.Al2O3.3 CaSO4.32H2O
Ettringite ( Candlot salt) 227% Volume increase
Na2SO4
2(3CaO.Al2O3.12H2O) + 3Na2SO4 . 10H2O
3CaO.AL2O3.3CaSO4.31H2O + 2Al(OH)3 + 6NaOH + 17H2O
MgSO4
REACTION WITH C3A
CaSO4.2H2O
3CaO.2SiO2.aq + MgSO4.7H2O
CaSO4.2H2O + Mg(OH)2 + SiO2.aq
Ettringite
Worst Effect: Attack to CSH besides C3A & Ca(OH)2
SULFATE REACTIONS
85
* WHITE STAINS
* CRACKS AT CORNERS & EDGES
* PEELING - DROPS
* SOFTENING - FRIABILITY
WATER MOVEMENT (WETTING&DRYING CYCLES ACCELERATES THE REACTION)
SIGNS
DANGER LIMITS IN WATER
IN SOIL
TS3440 3000 ppmSO4-2
MILD 600 ppmSO4-2
2000 ppmSO4-2
SEVERE 2000 ppmSO4-2
5000 ppmSO4-2
SULFATE ATTACK
86
DANGER LIMITS ACCORDING TO ACI 201
87
Negligible 0.00 – 0.10 0 - 150
Effect Soluble (SO4
-2) %
IN SOIL IN WATER
SO4-2 mg/lt
Moderate 0.10 – 0.20 150 - 1500
Severe 0.20 – 2.00 1500 - 10000
Very severe over 2.00 over 10000
DAMAGED WATER CHANNEL
88
PIPES LEFT ON SOILS RICH WITH SULFATE
89
DAMAGED BRIDGE COLUMN
90
SULFATE TEST RESULTS (84 days of testing period)
91
Test specimen Control specimen
PREVENTATIVE MEASURES
IMPERMEABLE CONCRETE
USING CEMENT with LOW C3A CONTENT
STABILIZATION of LIME (Ca(OH)2) with POZZOLANS
CONCRETE MUST BE INSULATED if NECESSARY
C3A %8 CEMENT MODERATE RESISTANT to SULFATE
C3A %5 CEMENT HIGHLY RESISTANT to SULFATE
92
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) C30/37 C30/37 C35/45
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 93
