B35 TANIM.pdf
-
Upload
yasin-aykanat -
Category
Documents
-
view
48 -
download
0
Transcript of B35 TANIM.pdf
-
7/21/2019 B35 TANIM.pdf
1/79
Concrete science and technology
Bridge between materials science, concrete
technology, execution and design of concretestructures
Lecture 10.09.2010
Mix design
-
7/21/2019 B35 TANIM.pdf
2/79
September 17, 2010 2
Cement
When happiness was a common thing
Sand Aggregate
Water
B25
B35B45
Concrete
-
7/21/2019 B35 TANIM.pdf
3/79
It has becomecomplicated
Gravel
Sand
Cement
Water
Slag
Fly ash
Silica fume
FillersSteel FibersPolymer fibersAccelerator
Retarder
Stabilizer
Air entrainer
Superplasticizer
Water
entrainer
Recycled aggregates
B15
B35
B45
B55
B65
B75
B85
B95
B105
B120
B200
B800
Light weight Concrete
Selfcompacting concrete
Fibre reinforced concrete
Property defined concrete
-
7/21/2019 B35 TANIM.pdf
4/79
September 17, 2010 4
Mix design procedureDutch standard procedure (ordinary concrete mixtures)
Phases in mix design process1. Choice of materials
2. Determination of composition of cement paste
3. Determination of aggregate (sand and gravel)
4. Check of volumes and mass (uitleveringsberekening)5. Check of chloride content
fccmfcck
Pre-phase:
1. Designer defines required strength (C/B value) and specific mass
2. Location and environment determine environmental class
3. Adopted execution method determines consistency
C-value
B-value
B-value
-
7/21/2019 B35 TANIM.pdf
5/79
September 17, 2010 5
Mix design procedureDutch standard procedure
Phases in mix design process
1. Choice of materials Aspects:
1. Availability2. Properties of raw materials (chemical, physical, mechanical)3. Price
2. Determination of composition of cement paste
1. Strength of the concrete
2. Norm strength of the cement paste
3. Water/binder ratio
4. Air content
5. Water and cement content
3. Determination of percentages sand and gravel (Workability!)1. Fuller method
2. Method of Rengers-Anthonisse (Currently used Dutch mixtures)
-
7/21/2019 B35 TANIM.pdf
6/79
September 17, 2010 6
Mix design procedureDutch standard procedure Design criteria
Strength
Workability (consistency classes 1, 2, 3,4)
Particle size distribution aggregate
Max. particle size aggregate
Percentage of fine material (< 250 m)
Amount of water
Durability
Specific mass (type of aggregate) Aesthetics (Color)
Chloride content (check)
-
7/21/2019 B35 TANIM.pdf
7/79
September 17, 2010 7
Strength
-
7/21/2019 B35 TANIM.pdf
8/79
September 17, 2010 8
Transfer of forces inside skeleton
matrix
External loading
Strength:
1. Matrix2. Aggregate
3. Interfacial zone
Strength
-
7/21/2019 B35 TANIM.pdf
9/79
September 17, 2010 9
Norm strength of cement vs. Concrete strength
External loading
Strength
Concrete strength
Coarse aggregate
Sand
Mortar
Cement paste
-
7/21/2019 B35 TANIM.pdf
10/79
September 17, 2010 10
Relation cylinder/cube compressive strength
C-value
B-value
-
7/21/2019 B35 TANIM.pdf
11/79
September 17, 2010 11
Strength classes ENV 206 and VBT
ENV 2006 VBT 1996 (Dutch)
Strength class Char. Cylindercompr. Strength
[MPa]
Char. Cubecompr. Strength
[MPa]
Strength class Char. Cubecompr. Strength
[MPa]
-
C12/15
-
12
-
15
B5
B15
5
15
C16/20
C20/25
16
20
20
25
-
B25
-
25C25/30
C30/37
25
30
30
37
-
B35
-
35
C35/45
C40/50
35
40
45
50
B45
-
45
-
C45/55
C50/60
45
50
55
60
B55
-
55
-
-
7/21/2019 B35 TANIM.pdf
12/79
September 17, 2010 12
Concrete strength and norm strength N
c
w/c
bN.a(N)fccm +=
N = Norm strength of cement
Norm strength: mortar prisms 160x40x40 mm
s/c = 3:1, w/c = 0.5
a = 0.8 (0.75 - 0.85)
b = 25 (20 - 25)
c = 45 (40 50)
fccm
Strength
B-value
-
7/21/2019 B35 TANIM.pdf
13/79
Strength
class
Compressive strength (Norm strength)
N/mm2Begin
setting
min.
Shape
preser-
vation
mm
Initial strength
After 28 days
After 2
days
After 7
days
32.5
32.5 R
--
> 10
> 16
--
> 32.5
> 32.5
< 52.5
< 52.5
> 60 < 10
42.5
42.5 R
> 10
> 20
--
--
> 42.5
> 42.5
< 62.5
< 62.5
52.5
52.5 R
> 20
> 30
--
--
> 52.5
> 52.5
--
--
> 45
Boundary values: strength, begin setting and shape preservation
Table 2.6
(Norm strength: mortar prisms 160x40x40 mm, s/c = 3:1, w/c = 0.5)
-
7/21/2019 B35 TANIM.pdf
14/79
September 17, 2010 14
Type of
cement
code Norm strength N of cement [N/mm2]
1 day 2 days 3 days 28 days
Portland
cement
CEM I 32.5 R
CEM I 42.5 R
CEM I 52.5 R
10
19
29
17
30
39
25
35
44
48
58
63
Portland-
flyash
cementCEM II/B V32.5 R 13 22 25 49
Blast
furnace
slagcement
CEM III/A 32.5
CEM III/A 42.5
CEM III/B 32.5 LH
CEM III/BA 42.5
7
8
5
8
14
17
10
17
19
22
14
25
46
59
48
58
Guide values for mean norm strength N of currently used cements
Table 10.8
Strength
-
7/21/2019 B35 TANIM.pdf
15/79
September 17, 2010 15
cw/c
bN.a(N)fccm +=
Relationship betweenw/c and compressivestrength of concrete fordifferent strength
classes (= Normstrengths) of cement
Compre
ssivestren
gth
[MPa]
Strength
Water/cement ratio
Norm strength cementCompressivestrength
(N/mm2)
Strength
class
Compressive strength (Norm strength)N/mm2
Beginsettin
g
min.
Shapepreser
-vation
mm
Initial strength
Af ter 28 daysAfter 2
days
After 7
days
32.5
32.5 R
--
> 10
> 16
--
> 32.5
> 32.5
< 52.5
< 52.5
> 60 < 10
42.5
42.5 R
> 10
> 20
--
--
> 42.5
> 42.5
< 62.5
< 62.5
52.5
52.5 R
> 20
> 30
--
--
> 52.5
> 52.5
--
--
> 45
-
7/21/2019 B35 TANIM.pdf
16/79
Strength depends on maximum aggregate size
Biggerparticles result
in lowerstrength
(Generally because of
more intensivemicrocracking)
-
7/21/2019 B35 TANIM.pdf
17/79
September 17, 2010 17
Mixture parameters vs. Mixture properties
Parameter Strength Workability Durability
Water/cement ratio X
Type of cement X
Amount of cement
Aggregate (Fineness modulus)
Amount of fines (< 250 m)
Max. particle diameter aggregate XSlump (experimental)
Air content
Water demand
Curing regime
-
7/21/2019 B35 TANIM.pdf
18/79
September 17, 2010 18
Workability
-
7/21/2019 B35 TANIM.pdf
19/79
September 17, 2010 19
Workability
Classification:
No slump concrete (aardvochtig beton)
Semi-Plastic (half plastisch)
Plastic (plastisch)
Flowable (vloeibaar beton)
Influencing factors: Particle grading of aggregate (sieve line)
Maximum particle diameter
Percentage fine material (< 250 m)
Amount of water
(Super)plasticizers
-
7/21/2019 B35 TANIM.pdf
20/79
September 17, 2010 20
Consistency / Workability
Consistency
Consistency of the concrete determines:
Plasticity
Cohesion
Internal friction
Stability
Consistency tests:1. Compacting factor
2. Vebe test
3. Slump test
4. Flow table test
5. Viscometer
y stress
Rateof flow
-
7/21/2019 B35 TANIM.pdf
21/79
September 17, 2010 21
Walz vessel
Consistency
Consistency of sticky mixtures
Betoniek, 13/08
-
7/21/2019 B35 TANIM.pdf
22/79
September 17, 2010 22
Slump test (consistency 2, 3)
Consistency Cone of Abrams
De Rooij
-
7/21/2019 B35 TANIM.pdf
23/79
Consistency classes (Dutch)
Class Consistency Compacting
Factor
V = (400/400-s)
Slump test
mm
Flow table
test
mm
1 No slump > 1.26 < 40 ---
2
Half plastic
(semi -) 1.25 1.11 50 - 90 150 - 350
3 Plastic 1.1 1.05 100 - 150 360 - 480
4 Flowable --- > 160 490 - 600
Less preferable method
-
7/21/2019 B35 TANIM.pdf
24/79
September 17, 2010 24
Particle size of materials
Material size [m]
Gravel 4000 - 63000 Sand: Coarse 500 - 4000
Fine 63 - 200
Fly ash 1 - 200
Cement 0.5 100 Silica fume 0.1 0.15
Particle grading
-
7/21/2019 B35 TANIM.pdf
25/79
September 17, 2010 25Sand: fine, middle and coarse
fine
coarse
Particle size [mm]
% passing
middle
Particle grading
-
7/21/2019 B35 TANIM.pdf
26/79
Boundaries for workable mixtures
Mixtures 0 - 16 mm
Sieve opening [mm]
Cum.sieveres
iduein%(v/v)
A
B
C
Particle grading
Fine
coarse
0.125 0.250 0,500 1 2 C4 C8 C16
0
10
20
30
40
50
60
70
80
90
100
-
7/21/2019 B35 TANIM.pdf
27/79
Boundaries for workable mixtures
Fine
coarse
-
7/21/2019 B35 TANIM.pdf
28/79
September 17, 2010 28
Particle grading aggregate
Fineness modulus (sand and gravel):
100
residusievecumulativesumF =s
Sieves according
NEN 2560
Sieve residue (sand)
per sieve Cumulative
C4
2 mm
1 mm100 m
150 m
125 mrest
5.7
24.5
21.326.8
17.5
3.3
0.9
5.7
30.2
51.578.3
95.8
99.1
--
total 100.0 Fs
Particle grading
-
7/21/2019 B35 TANIM.pdf
29/79
September 17, 2010 29
Amount of sand and gravel in mixtureSand percentage Ps according to Rengers-Anthonisse:
Ps = 10 Fs + 28 + 0.05 z 0.08 C
Fs = Fineness modulus of the sand
z = Slump value [mm]
C = Cement content [kg/m3]
Gravel percentage: Pg = 100 - Ps
Note: Rengers-Anthonisse is applicable for currently used Dutch mixtures
Particle grading
-
7/21/2019 B35 TANIM.pdf
30/79
September 17, 2010 30
Maximum particle size Dmax
Maximum particle Dmax: largest sieve
diameter of the coarsest particle group
Criteria originate from:
1. Mixing, transport, pouring
2. Reinforcement layout
3. Cover on reinforcement
4. Free space between prestressing ducts
Particle grading
-
7/21/2019 B35 TANIM.pdf
31/79
September 17, 2010 31
Amount of fine material: < 250 m
Fine material (< 250 m) consists of: Cement Fillers and fine sand Air bubbles (Air entraining agents)
Minimumamount of fine material is related tomaximumparticle diameter
Maximum particle Dmax[mm]
Minimum amount of fine material (< 250 m)per m3 concrete
[l]
8
1631.5
140
125115
Table 10.5
Particle grading
-
7/21/2019 B35 TANIM.pdf
32/79
September 17, 2010 32
Measured air content of fresh
paste
% (v/v)
Effective air content per m3 concrete, to be
considered as fine material
[l]
2
3
4
56
--
10
20
3040
Table 10.6 Effective air content, to be considered as fine material
Air content in concrete
Air content affects workability, strengthand durability
1% air results in a strength reduction of about 5%
Air entraining agent
-
7/21/2019 B35 TANIM.pdf
33/79
Largest sieve [mm] 8 16 31.5 63
Grade area A-B A-C A-B A-C A-B A-C A-B A-C
Consistency 1
(slump < 40 mm)
Compaction factor > 1.26175 195 160 180 150 170 140 155
Consistency 2(slump 50 90 mm) 192 213 180 200 165 185 155 170
Consistency 3
Slump 100 150 mm 205 225 195 218 180 200 168 190
Guide values for water demand W of concrete [kg/m3 concrete]
Table 10.11
For consistency 4no guide values are given.
Higher consistency only by using (super)plasticizers
Dont add water to achieve consistency 4 Water demand
-
7/21/2019 B35 TANIM.pdf
34/79
September 17, 2010 34
Mixture parameters vs. Mixture properties
Parameter Strength Workability Durability
Water/cement ratio X X
Type of cement X
Amount of cement (X)
Aggregate (Fineness modulus sand Fs) X
Amount of fines (< 250 m) X
Max. particle diameter aggregate X XSlump (experimental) X
Air content X
Water demand X
Curing regime
-
7/21/2019 B35 TANIM.pdf
35/79
September 17, 2010 35
DurabilityEnvironmental classes
-
7/21/2019 B35 TANIM.pdf
36/79
September 17, 2010 36
Durability of concrete
Town of Bellefontaine, State of Ohio, USA, 1891
50 year concrete pavement
75 year concrete pavementGeorge Bartholomew
-
7/21/2019 B35 TANIM.pdf
37/79
September 17, 2010 37
Oresund Bridge (2000)
15 mm
Concrete
crack
Photo: Ingenieur 2007
-
7/21/2019 B35 TANIM.pdf
38/79
September 17, 2010 38
Durability & Environmental classes
Rebar corrosion
Carbonation-induced corrosion
Chloride-induced corrosion
ASR Alkali-Silica Reaction
Sulphate attack (sea water)
Leaching processes (acid attack)
Main points of concern:
-
7/21/2019 B35 TANIM.pdf
39/79
H2O, CO2
CaCO3
pH = 7 - 9
pH = 13
pH
Consumption
of Ca(OH)2
Rebar corrosion!
Rebarw
Carbonationinduced rebar corrosion
-
7/21/2019 B35 TANIM.pdf
40/79
September 17, 2010 40
Design lifetime of large infrastructural works:
100 - 150 years
Eastern Scheldt storm surge barrier
Chloride exposure
Freeze-thaw
Drying & wetting
(Micro)cracking
Risk of corrosion ofreinforcing steel
-
7/21/2019 B35 TANIM.pdf
41/79
September 17, 2010 41
Environmental classes (NEN)
Class Description of environment (Current Dutch code)
1
2
3
4
5
Dry
Humid
Humid in combination with de-icing salts
Sea water
Aggressive;
a: weakb: moderate
c: strong
d: very strong
-
7/21/2019 B35 TANIM.pdf
42/79
September 17, 2010 42
Type of aggressive
substance
No weak moderate strong Very
strong
pH>6.5 6.5 5.5 5.5 4.5 4.5 4.0 < 4.0
CO2 (dissolves lime)
[mg CO2/l] < 15 15-30 30-60 60-100 >100
Ammonium
[mg NH4+/l] < 15 15-30 30-60 60-100 >100
Magnesium
[mg NH4+/l]
< 100 100-300 300-1500 1500-3000 >3000
Sulphates
[mg SO42-/l]
< 200 200-600 600-3000 3000-6000 >6000
Aggresivity of solutions in water
Table 10.2
-
7/21/2019 B35 TANIM.pdf
43/79
Environmental classes
Class Description of environment (European code)
XO
XC
XD
XS
XF
XA
NO risk of corrosion or attack
Carbonation initiated corrosion
Chloride induced corrosion, not from sea water (De-icing)
Chloride induced corrosion - Sea water
Freeze-thaw attack, with and without de-icing salts
ChemicalAttack
Class Description of environment (Current Dutch code)
1
2
34
5
Dry
Humid
Humid in combination with de-icing saltsSea water
Aggressive; a: weak, b: moderate, c: strong, d: very strong
-
7/21/2019 B35 TANIM.pdf
44/79
Environmental classes NEN-EN 206-1
Class Description of environment
XO
X0
NO risk of corrosion or attack
Concrete without reinforcement, except classes XF and XA concrete with
reinforcement: very dry environment
XC
XC1
XC2
XC3
XC4
Carbonation initiated corrosion
Dry of constant wet
Wet, rarely dry
Intermediate moisture condition
Alternating wet and dry
XDXD1
XD2
XD3
Chloride induced corrosion, not from sea water (De-icing)Dry of constant wet
Wet, rarely dry
Alternating wet and dry
-
7/21/2019 B35 TANIM.pdf
45/79
Environmental classesEnvironmental classes Houses and buildingsHouses and buildings
Facade
Cellar wallBalcony
Cellar wall Cellar deck
Cellar f loor
Floors, walls (inside)
Fresh water
E i t l l NEN EN 206 1
-
7/21/2019 B35 TANIM.pdf
46/79
Environmental classes NEN-EN 206-1
Class Description of environment
XS
XS1
XS2
XS3
Chloride induced corrosion - Sea water
Salt containing air
Constant under water
Tidal zone, splash zone
XF
XF1
XF2XF3
XF4
Freeze-thaw attack, with and without de-icing salts
Non-saturated water, without de-icing salt
Non-saturated water, with de-icing saltSaturated water, without de-icing salt
Saturated water, with de-icing salt or sea water
XA
XA1
XA2
XA3
ChemicalAttack
Weak aggressive environment
Moderate aggressive environment
Severe aggressive environment
-
7/21/2019 B35 TANIM.pdf
47/79
Environmental classes Houses and buildings
Coastal area
Facade
Cellar wall
Floors, walls (inside)
Cellar floor slab
-
7/21/2019 B35 TANIM.pdf
48/79
Environmental classes Industrial buildings (XA)
-
7/21/2019 B35 TANIM.pdf
49/79
Environmental classes
Industrial buildings and infrastructural works (XA, XF)
D bilit it i
-
7/21/2019 B35 TANIM.pdf
50/79
September 17, 2010 50
Durability criteria
Consequences for mix design
2. Water/cement (binder) ratio
General: Denser cement paste gives higher durability
1. Type of cement
3. Cement content
4. Curing (Give it a week)
Prevent early evaporation
Better curing gives higher degree of hydration
Keep temperature low
Environmental classes (NEN)
-
7/21/2019 B35 TANIM.pdf
51/79
September 17, 2010 51
Environmental classes (NEN)
Class Description of environment (Current Dutch code)
1
2
3
4
5
Dry
Humid
Humid in combination with de-icing salts
Sea water
Aggressive;
a: weak
b: moderate
c: strong
d: very strong
Criteria for concrete mixtures for different environmental classes
-
7/21/2019 B35 TANIM.pdf
52/79
Microlab Faculty of Civil Engineering and Geosciences
Environmental class
1 2 3 4 5a 5b 5c,d
+aea +aea
W/c (w/b)
Plain
Reinforced
Prestressed
--
0.65
0.60
0.70
0.55
0.55
0.55
0.55
0.55
0.45
0.45
0.45
0.55
0.55
0.55
0.45
0.45
0.45
0.55
0.55
0.55
0.50
0.50
0.50
0.45
0.45
0.45
Min. cement/ binder
[kg/m3]
Plain
Reinf. & prestress
Grading A-B
Grading A-C
Discontineous
150
260
260
260
200
280
280
280
280
280
300
300
280
280
300
300
280
280
300
300
300
300
300
300
300
300
300
300
Table 10.3 aea = air entraining agent
Criteria for concrete mixtures for different environmental classes
-
7/21/2019 B35 TANIM.pdf
53/79
September 17, 2010 53
Environmental class
1 2 3 4 5a 5b 5c,d
+aea +aea
Min. air content
[%] for aggr. Diam.
D = 63 mm
D = 31.5 mm
D = 16 mmD = 8 mm
--
--
----
--
--
----
3.0
3.5
4.05.0
--
--
----
3.0
3.5
4.05.0
--
--
----
--
--
----
--
--
----
--
--
----
Type of cement Sulphate
resistant
BFSC
Sulphate resistant
cement
Table 10.3 (cont.)
aea = air entraining agent (luchtbelvormer)
Mixture parameters vs Mixture properties
-
7/21/2019 B35 TANIM.pdf
54/79
September 17, 2010 54
Mixture parameters vs. Mixture properties
Parameter Strength Workability Durability
Water/cement ratio X X X
Type of cement X X
Amount of cement (X) X
Aggregate (Fineness modulus) X X
Amount of fines (< 250 m) X
Max. particle diameter aggregate X X X
Slump (experimental) X
Air content X X
Water demand X
Curing regime X
-
7/21/2019 B35 TANIM.pdf
55/79
September 17, 2010 55
Mix design
Mixture for specified environment
Example
Mix design - Example
-
7/21/2019 B35 TANIM.pdf
56/79
September 17, 2010 56
Mix design - Example
Project: Infrastructure construction Mass concrete
Environmental class 2 (Dutch code)
Materials: Sand and gravel given (see table)
Mix design - Example
Grading sand and gravel (in stock)
-
7/21/2019 B35 TANIM.pdf
57/79
September 17, 2010 57
Grading sand and gravel (in stock)
Sieve according NEN2560
Cumulative sieve residue [%]
sand gravel
C 31.5
C16
C8
C4
2 mm
1 mm
500 m
250 m
125 m
--
--
--
3
9
28
60
94
100
--
28
70
94
100
100
100
100
100Fineness modulus F 2.94 6.92
Mix design - Example
6% sand < 250 m
Mix design
-
7/21/2019 B35 TANIM.pdf
58/79
September 17, 2010 58
Mix design
The unknowns are:
Concrete strength
Type of cement
w/c
Amount of water
Amount of cement
Amount of air
Amount of sand
Amount of gravel
Air?
Water?
Cement?
Sand?
Gravel? workability
durability
Mix design - Considerations
-
7/21/2019 B35 TANIM.pdf
59/79
Mix design Considerations
Mass concrete: Low heat cementCEM III/B (Slag: 66-80%)
Required strength: B25 (= C20/25)
fcck= 25 MPafccm = 32 MPa
Pouring with container: Consistency class 2
Mix design - Example
Class Consistency Compacting
Factor
V = (400/400-s)
Slump test
z
mm
Flow table
test
mm
1 No slump > 1.26 < 40 ---
2Half plastic
(semi -)1.25 1.11 50 - 90 150 - 350
3 Plastic 1.1 1.05 100 - 150 360 - 480
4 Flowable --- > 160 490 - 600
Slump z = 50 90 mm
z = 70 mm
Mix design
-
7/21/2019 B35 TANIM.pdf
60/79
September 17, 2010 60
Mix design
The unknowns are:
Concrete strength B25
Type of cement CEMIII-B
w/c .
Amount of water .
Amount of cement .
Amount of air .
Amount of sand .
Amount of gravel .
Air?
Water?
Cement?
Sand?
Gravel?
-
7/21/2019 B35 TANIM.pdf
61/79
September 17, 2010 61
Mix design - Example
Strength
Mix design - Example
Guide values for mean norm strength N of currently used cements
-
7/21/2019 B35 TANIM.pdf
62/79
September 17, 2010 62
Type of
cement
code Norm strength N of cement [N/mm2]
1 day 2 days 3 days 28 days
Portland
cement
CEM I 32.5 R
CEM I 42.5 R
CEM I 52.5 R
10
19
29
17
30
39
25
35
44
48
58
63
Portland-
flyashcement CEM II/B V32.5 R 13 22 25 49
Blast
furnace
slag
cement
CEM III/A 32.5
CEM III/A 42.5
CEM III/B 32.5 LHCEM III/BA 42.5
7
8
58
14
17
1017
19
22
1425
46
59
4858
Table 10.8
Mix design - Example
Concrete strength and Norm strength N
-
7/21/2019 B35 TANIM.pdf
63/79
September 17, 2010 63
Concrete strength and Norm strength N
c
w/c
bN.a(N)fccm +=
N = Norm strength of cement = 48 MPa (for CEM III/B)
a = 0.8; b = 25; c = 45
Required w/c = 0.65
(Note: Norm strength refers to mortars with w/c=0.5)
fccm
Mix design - Example
Check whether w/c is OK in view of durability requirements!! (Table 10.3)
a = 0.8 (0.75 - 0.85)
b = 25 (20 - 25)
c = 45 (40 50)
Mix design
-
7/21/2019 B35 TANIM.pdf
64/79
September 17, 2010 64
Mix design
The unknowns are:
Concrete strength B25
Type of cement CEMIII-B
w/c 0.65
Amount of water .
Amount of cement . Amount of air .
Amount of sand .
Amount of gravel .
Air?
Water?
Cement?
Sand?
Gravel?
-
7/21/2019 B35 TANIM.pdf
65/79
September 17, 2010 65
Mix design - Example
Strength
Mix design - Example
Strength gives first indication about w/c (w/c = 0.65)
Is this w/c also OK for durability?
Criteria for concrete mixtures for different environmental classes
Table 10 3
-
7/21/2019 B35 TANIM.pdf
66/79
Environmental class
1 2 3 4 5a 5b 5c,d
+aea +aea
W/c (w/b)Plain
Reinforced
Prestressed
--
0.65
0.60
0.70
0.55
0.55
0.55
0.55
0.55
0.45
0.45
0.45
0.55
0.55
0.55
0.45
0.45
0.45
0.55
0.55
0.55
0.50
0.50
0.50
0.45
0.45
0.45
Min. cement/binder [kg/m3]
(Plain concrete)
Reinf. & prestress
Grading A-B Grading A-C
Discontineous
150
260
260
260
200
280
280
280
280
280
300
300
280
280
300
300
280
280
300
300
300
300
300
300
300
300
300
300
Table 10.3
aea = air entraining agent
Concrete strength and Norm strength N
-
7/21/2019 B35 TANIM.pdf
67/79
g g
c
w/c
bN.a(N)fccm +=
N = Norm strength of cement = 48 MPa (for CEM III/B)
a = 0.8; b = 25; c = 45
(Note: Norm strength refers to mortars with w/c=0.5)
Required w/c = 0.65
For Env.Class 2 (table 10.3) w/c = 0.55
For sake of safety: w/c = 0.53
fccm
Mix design - Example
Mix design
-
7/21/2019 B35 TANIM.pdf
68/79
September 17, 2010 68
Mix design
The unknowns are:
Concrete strength B25
Type of cement CEMIII-B
w/c 0.65 0.53
Amount of water .
Amount of cement . Amount of air .
Amount of sand .
Amount of gravel .
Air?
Water?
Cement?
Sand?
Gravel?
Air content and water demand
-
7/21/2019 B35 TANIM.pdf
69/79
September 17, 2010 69
Air content: No requirements
Assume: Va< 2%, e.g. 1%
Then no effect on strength!
Water demand: Depends on aggregate grading!
(Table 10.11)
Mix design - Example
Guide values for water demand W of concrete [kg/m3 concrete]
-
7/21/2019 B35 TANIM.pdf
70/79
Largest sieve [mm] 8 16 31.5 63
Grade area A-B A-C A-B A-C A-B A-C A-B A-C
Consistency 1(slump < 40 mm)
Compaction factor > 1.26175 195 160 180 150 170 140 155
Consistency 2
(slump 50 90 mm) 192 213 180 200 165 185 155 170
Consistency 3
Slump 100 150 mm205 225 195 218 180 200 168 190
Table 10.11
For consistency 4no guide values are given.
Higher consistency only by using (super)plasticizers
Dont add water to achieve consistency 4
Air content and water demand
-
7/21/2019 B35 TANIM.pdf
71/79
September 17, 2010 71
Air content: No requirements
Assume: Va< 2%, e.g. 1%
Then no effect on strength!
Water demand (Table 10.11)Consistency class 2
Dmax < 32 mm
Grading lines A-B
Vw = 165 l/m3
Mix design - Example
Cement content and paste volume
-
7/21/2019 B35 TANIM.pdf
72/79
September 17, 2010 72
Mix design - Example
Cement content C:
W/C = 0.53
Vw = 165 l/m3 = 165 kg/m3
Note: Environmental Class 2 (Table 10.3): C> 280 kg/m3: OK
C = 311 kg/m3
Criteria for concrete mixtures for different environmental classes
Table 10.3
-
7/21/2019 B35 TANIM.pdf
73/79
Environmental class
1 2 3 4 5a 5b 5c,d
+aea +aea
W/c (w/b)
Plain
Reinforced
Prestressed
--
0.65
0.60
0.70
0.55
0.55
0.55
0.55
0.55
0.45
0.45
0.45
0.55
0.55
0.55
0.45
0.45
0.45
0.55
0.55
0.55
0.50
0.50
0.50
0.45
0.45
0.45
Min. cement/ binder
[kg/m3]
Plain
Reinf. & prestress
Grading A-B
Grading A-C
Discontineous
150
260
260
260
200
280
280
280
280
280
300
300
280
280
300
300
280
280
300
300
300
300
300
300
300
300
300
300
aea = air entraining agent
Mix design
-
7/21/2019 B35 TANIM.pdf
74/79
September 17, 2010 74
The unknowns are:
Concrete strength B25
Type of cement CEMIII-B
w/c 0.65 0.53
Amount of water 165 l.
Amount of cement 311 kg/m3
Amount of air 10 l (=1%)
Amount of sand .
Amount of gravel .
Air?
Water?
Cement?
Sand?
Gravel?
Cement content and paste volume
-
7/21/2019 B35 TANIM.pdf
75/79
September 17, 2010 75
Mix design - Example
Cement content C:
W/C = 0.53
Vw = 165 l/m3 = 165 kg/m3
Note: Environmental Class 2 (Table 10.3): C> 280 kg/m3: OK
C = 311 kg/m3
Cement paste volume:
Slag cement: C = 311 kg/m3 (311/2950) = 0.102 m3
Water: Vw= 165 kg/m3 = 0.165 m3
Air: Va = 1% = 0.010 m3
Cement paste volume Vcp = 0.280 m3
Sand + coarse aggregate V = 0.720 m3
Amount of sand and gravel
-
7/21/2019 B35 TANIM.pdf
76/79
September 17, 2010 76
Sand percentage Ps according to Rengers-Anthonisse:
Ps = 10 Fs + 28 + 0.05 z 0.08 C
Fs = 2.94 (Fineness modulus of sand)
z = 70 mm (Slump value between 50 and 90 mm)
C = 311 kg/m3 (Cement content)
Ps = 10 2.94 + 28 + 0.05 70 0.08 311
Ps = 36%
Gravel percentage: Pg = 100 36 = 64%
Mix design - Example
Check amount of fine material < 250 m
-
7/21/2019 B35 TANIM.pdf
77/79
Fine material (< 250 m) consists of Cement (0.102 l)
Fillers and fine sand (see sieve analysis: 6% of sand)
Air bubbles (Air entraining agents) (--)
Maximum particle Dmax
[mm]
Minimum amount of f ine material ( 115 l OK
Mix design - Example
Sieve according NEN2560
Cumulative sieve residue [%]
sand gravel
C 31.5
C16
C8
C4
2 mm
1 mm
500 m250 m
125 m
--
--
--
3
9
28
6094
100
--
28
70
94
100
100
100100
100
Fineness modulus F 2.94 6.92
Mix design
-
7/21/2019 B35 TANIM.pdf
78/79
September 17, 2010 78
The unknowns are:
Concrete strength B25
Type of cement CEMIII-B w/c 0.65 0.53
Amount of water 165 l.
Amount of cement 311 kg/m3
Amount of air 10 l (=1%)
Amount of sand 260 l.
Amount of gravel 460 l.
Air?
Water?
Cement?
Sand?
Gravel?
Mix design Summary
-
7/21/2019 B35 TANIM.pdf
79/79
September 17, 2010 79
RequirementsStrength B25
Environmental class 2
Consistency class 2
Mixture composition
W/c 0.53
Cement 311 kg/m3
Water 165 kg/m3
Air 10 l
Sand 36% of 720 l = 260 l
Gravel 64% of 720 l = 460 l
Mix design - Example
In case of new types of mixtures: Always test mixtures!!