2. 2
INTRODUCTION
Concrete is obtained by mixing cement, fine aggregate, coarse
aggregate, water and admixtures in required proportions. The
mixture when placed in forms and allowed to cure becomes
hard like stone.
The hardening is caused by chemical action between water and
the cement due to which concrete grows stronger with age.
It is the most widely-used man-made construction material in
the world.
4. 4
CEMENT
Cement and water forms the ‘active’ component of concrete, while
the inactive group comprises the fine and coarse aggregates.
The cement and water form a paste that hardens and bonds the
aggregates together.
Types of Cement
Although around 18 types of cements are recognized by BIS, more
commonly used ones are:
•
•
•
•
•
•
Ordinary Portland Cement 33, 43, & 53 grade OPC,
Blended Cements (PPC and PSC).
Sulphate Resisting Cement (SRC),
Low Heat Portland Cement (LHPC),
Hydrophobic Portland Cement,
Colored Cement (White Cement).
5. 5
AGGREGATES
• They are cheaper than cement and impart greater volume
stability and durability to concrete.
• The main purpose is to provide bulk to the concrete.
• Some of the aggregates may be chemically active.
CLASSIFICATION
•
•
•
•
Geological origin – natural and artificial
Size – fine, coarse and all-in
Shape – rounded, irregular, angular, flaky and elongated
Unit weight – normal-weight, heavyweight and lightweight
6. 6
W ATER
•
•
•
•
•
•
The most important and least expensive ingredient of concrete.
One part of the water is used in the hydration of cement to form
the binding matrix.
The remaining water affords lubrication and workability to the
concrete.
Water-cement ratio depends on the grade of concrete, its
workability, durability, nature and type of aggregates etc.
Potable water is ideal for concreting.
Seawater may be used in PCC.
7. 7
ADMIXTURES
Added to the concrete immediately or during mixing to modify its
properties in the fresh or hardened state.
Types:
•
•
•
•
•
•
•
•
Accelerators - speed up the initial set of concrete.
Retarders – delay the setting time of concrete mix.
Plasticizers and Super-plasticizers - water reducers.
Air entraining admixtures
Water proofers
Pigments
Corrosion-inhibiting chemicals
Antifungal admixtures
8. 8
CONCRETE MIX PROPORTIONING
• Determination of the proportion of the concrete
ingredients such as cement, fine aggregate, coarse
aggregate, water and admixtures is called concrete
mix.
• A proper mix design only can gives the specified
properties such as workability, strength,
permeability and durability with economy.
Types:
1. Nominal mix
2. Design mix
9. 9
TYPES OF MIX PROPORTIONING
1. Nominal mix:
• As per IS456:2000, fixed mix proportions are
available for various grade of concrete is called
nominal or standard mix. Usually, this method is
suitable the grade of concrete up to M20 or lesser.
Example:
Grade of concrete Nominal Mix proportions
M10 1:3:6
M15 1:2:4
M20 1:1:3
10. 10
TYPES OF MIX PROPORTIONING
2. Design mix:
• In this type, the concrete mix proportioning is
determined on the basis of requirements of
concrete on fresh and hardens properties (target
mean strength).
• And to get desired strength, special procedures is to
be followed which are available in IS10262-2009
and IS456-2000.
• Deign mix will give desired properties as like
• More suitable for higher grade of concrete
11. 11
CONCRETE MIX DESIGN
DEFINITION
“ Mix Design is the science of determining the relative
proportions of the ingredients of concrete to achieve the
desired properties in the most economical way.”
12. 12
PRINCIPLES OF MIX DESIGN
1 The environment exposure condition for the structure
2 The grade of concrete, their characteristic strength’s and
standard deviations
3 The type of cement
4 The types and sizes of aggregates and their sources of supply
5 The nominal maximum sizes of aggregates
6 Maximum and minimum cement content in kg/m3
7 Water cement ratio
8 The degree of workability of concrete based on placing
conditions
13. 13
9 Air content inclusive of entrained air
10 The maximum/minimum density of concrete
11 The maximum/minimum temperature of fresh concrete
12 Type of water available for mixing and curing
13 The source of water and the impurities present in it.
14. 14
WORKABILITY
“that property of freshly mixed concrete which determines the
ease and homogeneity with which it can be mixed, placed,
consolidated and finished.”
DURABILITY
“the resistance to weathering action due to environmental
conditions such as changes in temperature and humidity,
chemical attack, abrasion, frost and fire.”
15. STANDARD DEVIATION
• Standard deviation generally indicates the deviation of a set
of variables (RESULTS) from the mean value.
• Also, a low value of standard deviation indicates more
consistent results. On the other hand, higher values
represent inconsistent results.
• Mathematically standard deviation is stated as, the root
mean square deviation of all the result. This is denoted by σ.
Where, x = Compressive strength of sample
μ = Average strength of Samples (x/n)
n = Total number of samples for a batch of mix
15
16. 16
FACTOR AFFECTING THE MIX DESIGN /
STRENGTH OF CONCRETE
1. Grade designation:
Higher grade of concrete (M80 or above) will
influence the mix design and subsequent
strength of concrete due to the requirements of
materials quality, degree of supervision,
admixtures etc.
2. Type and grade of cement:
For very high compressive strength of concrete,
Portland cement of 53 grade can be used.
Similarly, where earlier strength is required,
rapid hardening cement can be used
17. 17
FACTOR AFFECTING THE MIX DESIGN /
STRENGTH OF CONCRETE
3. Maximum nominal size of coarse aggregates:
If the size of the aggregate is increased, workability
will be increased but the strength will be decreased.
4. Grade of combined aggregates:
Single sized aggregate may lead the bleeding and
segregation of the concrete mix and subsequent
strength loss.
5. Fineness modulus:
In order to get proper workability and strength, the
fineness modulus value for fine and coarse aggregate
should be within the prescribed value.
18. 18
FACTOR AFFECTING THE MIX DESIGN /
STRENGTH OF CONCRETE
6. Water cement ratio:
More water cement ratio will give high
workability and reduction in strength. Less water
cement ratio makes the concrete difficult to
handle.
7. Quality control:
The concrete materials quality and degree of
supervision also may affect the mix design
process and strength of concrete. Poor materials
will lead the strength reduction.
19. 19
ADVANTAGES / IMPORTANCES OF
CONCRETE MIX DESIGNS
1. Good quality concrete
2. Nominal mix concrete
3. Best use of available materials
4. Desired Concrete Properties
20. 20
Methods of mix design
1. ACI mix design method
2. DOE method
3. USBR mix design
4. British mix design
5. Mix design for pumpable concrete
6. Mix design using BIS guidelines (being in
syllabus)
21. 21
MIX DESIGN USING BIS GUIDELINES / DATA’S
REQUIRED FOR MIX DESIGN
1. Grade of concrete
2. Maximum size of aggregate
3. Minimum cement content
4. Maximum W/C ratio
5. Workability in terms of slump
6. Exposure condition
7. Maximum temperature at the pouring point
8. Early age strength (if required)
9. Grading zone of fine aggregate
10. Type of aggregate
11. Maximum cement content
12. Admixture used
13. Specific gravity of all the materials used
14. Moisture content (free)
22. MIX DESIGN PROCEDURE AS PER
IS10262:2009
1. Target mean strength of concrete (fckʹ):
fckʹ = fck + 1.65 S (N/mm2)
Where, fck = Characteristics compressive strength at 28 days
S = Standard deviation (Ref: IS10262:2009, Table 1)
22
23. MIX DESIGN PROCEDURE AS PER
IS10262:2009 (cont.)
2. Selection of water cement ratio (w/c):
From Table 5 of IS456:2000, it can be taken depending upon
the exposure conditions (0.4 – 0.6).
23
24. MIX DESIGN PROCEDURE AS PER
IS10262:2009 (cont.)
3. Selection of water content:
From Table 2 of IS10262:2009, maximum water content = 186
kg (25 mm – 50 mm slump)
[For additional slump 3% may be added for every 25 mm slump]
24
25. 25
MIX DESIGN PROCEDURE AS PER
IS10262:2009 (cont.)
4. Calculation of cement content:
• It can be calculated by W/C ratio
• Check by minimum cement content from Table 5 of
IS456:2000.
Example:
W=186 kg
W/C = 0.45
C = W/0.45 = 186/0.45 = 413.33kg
26. MIX DESIGN PROCEDURE AS PER
IS10262:2009 (cont.)
5. Volume of coarse aggregate and fine aggregate content:
• The proportion of volume of coarse aggregate and fine
aggregate can be determined from Table 3 of IS10262:2009
(selected depending upon the fine aggregate ZONE).
26
27. MIX DESIGN PROCEDURE AS PER
IS10262:2009 (cont.)
6. Mix calculation:
The mix calculation per unit volume of concrete shall be as follows;
(a) Volume of concrete = 1 m3
(b) Volume of cement/Cement + admixture =
(c) Volume of water =
(d) Volume of chemical admixtures (If need) =
(e) Volume of aggregates (fine and coarse) = a-(b+c+d)
(f) Mass of coarse aggregate (CA) = e x Volume of CA x Specific gravity of CA x
1000
(g) Mass of fine aggregate (FA) = e x Volume of FA x Specific gravity of FA x
1000
27
28. 28
MIX DESIGN PROCEDURE AS PER
IS10262:2009 (cont.)
7. Mix proportion:
Cement = kg/m3
Water = kg/m3
Fine aggregate = kg/m3
Coarse aggregate = kg/m3
Chemical admixture
Water cement ratio
=
=
kg/m3
29. 29
IS10262:2009 (cont.)
8. Mix Ratio:
Cement (1) : Fine aggregate/Cement : Coarse aggregate / Cement
Example:
1:2:4
MIX DESIGN(1P
) RO
: CEDURE AS PER
:
30. 30
Design of M30 concrete mix as per IS:10262-2009, concrete mix proportioning
guidelines. The following are the design data’s for proportioning:
: M30
: OPC 43 grade confirming to IS8112
: 20 mm
: 350 kg/m3
: 0.50
: 25-50 mm (slump)
: Moderate
: Good
: Crushed angular aggregate
: 450 kg/m3
: Not recommended
: 3.15
: 2.68
: 2.65
Grade designation
Type of cement
Maximum nominal size of aggregate
Minimum cement content
Maximum water cement ratio
Workability
Exposure condition
Degree of supervision
Type of aggregate
Maximum cementcontent
Chemical admixture
Specific gravity of cement
Specific gravity of Coarse aggregate
Specific gravity of Fine aggregate
Water absorption:
: 0.6 percent
: 1 percent
: Nil
: Nil
Coarse aggregate
Fine aggregate
Free surface moisture:
Coarse aggregate
Fine aggregate
Sieve analysis:
Fine aggregate : Confirming to Zone I of IS383
31. 31
Solution:
1. Target mean strength:
fckʹ = fck + 1.65 S
By referring Table 1 of IS10262:2009, S= 5
fckʹ = 30+ 1.65 x 5 = 38.25 N/mm2
2. Selection of water cement ratio:
By referring Table 5 of IS456:2000.
Adopt 0.45 < 0.5 (maximum water cement ratio for
moderate exposure)
32. 32
3. Selection of water content:
By referring Table 2 of IS 10262:2009
Water content (W) for 25mm-50mm slump is
186 litres
4. Calculation of cement content:
Water cement ratio is = 0.45
i.e, W/C = 0.45
Therefore cement content, C = W/0.45 =
186/0.45 = 413 kg/m3 > 350 kg/m3 HenceO.K.
33. 33
EXAMPLE-1 (Cont)
5. Volume of coarse aggregate and fine
aggregate:
From Table 3 of IS10262:2009 for Zone I fine
aggregate with 20 mm sized aggregate;
Coarse aggregate volume = 0.6
Fine aggregate volume = 1-0.6 = 0.4
34. EXAMPLE-1 (Cont)
The mix calculation per unit volume of concrete shall be as
follows;
(a) Volume of concrete = 1 m3
(b) Volume of cement/ admixture =
= = 0.131 m3
(c) Volume of water =
= = 0.186 m3
34
35. EXAMPLE-1 (Cont)
(d) Volume of chemical admixtures (If need)
=
= 0
(e) Volume of aggregates (fine and coarse) = a-(b+c+d)
= 1-(0.131+0.186+0) = 0.683 m3
(f) Mass of coarse aggregate (CA) = e x Volume of CA x Specific gravity of
CA x 1000
= 0.683 x 0.6 x 2.68 x 1000 = 1098 kg
(g) Mass of fine aggregate (FA) = e x Volume of FA x Specific gravity of
FA x 1000
= 0.683 x 0.4 x 2.65 x 1000 = 724kg
35
36. 36
EXAMPLE-1 (Cont)
7. Mix proportion for trial 1:
= 413 kg/m3
= 186 kg/m3
=724 kg/m3
= 1098 kg/m3
= 0.45
Cement (C)
Water (W)
Fine Aggregate (FA)
Coarse aggregate (CA)
Water cement ratio (w/c)
8. Trial Mix ratio:
1: 1.75 : 2.65
37. 37
EXAMPLE-2(Nov/Dec 2016, Apr/May 2017)
Design of M40 concrete mix as per IS:10262-2009, concrete mix proportioning
guidelines. The following are the design data’s for proportioning:
: M40
: OPC 43 grade confirming to IS8112
: 20 mm
: 320 kg/m3
: 0.45
: 100 mm (slump)
: Severe (for reinforced concrete)
: Pumping
: Good
: Crushed angular aggregate
: 450 kg/m3
: Superplasticizer confirming to IS9103
: 3.15
: 2.74
: 2.74
Grade designation
Type of cement
Maximum nominal size of aggregate
Minimum cement content
Maximum water cement ratio
Workability
Exposure condition
Method of concrete placing
Degree of supervision
Type of aggregate
Maximum cementcontent
Chemical admixture
Specific gravity of cement
Specific gravity of Coarse aggregate
Specific gravity of Fine aggregate
Water absorption:
: 0.5 percent
: 1 percent
: Nil
: Nil
Coarse aggregate
Fine aggregate
Free surfacemoisture:
Coarse aggregate
Fine aggregate
Sieve analysis:
Fine aggregate : Confirming to Zone I of IS383
38. 38
EXAMPLE-2 (Cont)
Solution:
1. Target mean strength:
fckʹ = fck + 1.65 S
By referring Table 1 of IS10262:2009, S= 5
fckʹ = 40+ 1.65 x 5 = 48.25 N/mm2
2. Selection of water cement ratio:
By referring Table 5 of IS456:2000.
Adopt 0.4 < 0.45 (maximum water cement ratio for
moderate exposure)
39. 39
EXAMPLE-2 (Cont)
3. Selection of water content:
By referring Table 2 of IS 10262:2009
Water content (W) for 25mm-50mm slump is 186 litres
Water content (W) for 100 mm slump is = 186 +
6/100*186= 197 Litres
[3% water is increase for every 25 mm slump
increments]
In this mix design, superplasticizer is going to use,
hence the water content can be reduced up to 30%.
Therefore revised water content = 197 – 0.3x197 = 138
Litres.
40. 40
EXAMPLE-2 (Cont)
4. Calculation of cement content:
Water cement ratio is = 0.4
i.e, W/C = 0.4
Therefore cement content, C = W/0.45 =
138/0.45 = 345 kg/m3 > 320 kg/m3 HenceO.K.
41. 41
EXAMPLE-2 (Cont)
5. Volume of coarse aggregate and fine aggregate:
From Table 3 of IS10262:2009 for Zone I fine
aggregate with 20 mm sized aggregate and w/c
ratio of 0.5;
Coarse aggregate volume
correction of w/c ratio)
= 0.6+0.02 (for
= 0.62
It can be reduce to 10%, for pumpable concrete (Ref:IS10262-
2009, C-4.4.1)
= 0.9 x 0.62 = 0.56
Fine aggregate volume = 1-0.56 = 0.44
42. EXAMPLE-2 (Cont)
The mix calculation per unit volume of concrete shall be as
follows;
(a) Volume of concrete = 1 m3
(b) Volume of cement/ admixture =
= = 0.109 m3
(c) Volume of water =
= = 0.138 m3
42
43. EXAMPLE-2 (Cont)
(d) Volume of chemical admixtures (If need)
=
= = 0.0058
(e) Volume of aggregates (fine and coarse) = a-(b+c+d)
= 1-(0.109+0.138+0.0058)
= 0.75 m3
(f) Mass of coarse aggregate (CA) = e x Volume of CA x Specific gravity of
CA x 1000
= 0.75 x 0.56 x 2.74 x 1000 = 1151 kg
(g) Mass of fine aggregate (FA) = e x Volume of FA x Specific gravity of
FA x 1000
= 0.75 x 0.44 x 2.74 x 1000 = 904kg
43
44. 44
EXAMPLE-2 (Cont)
7. Mix proportion for trial 1:
Cement (C) = 345 kg/m3
Water (W) = 138 kg/m3
Fine Aggregate (FA) = 904 kg/m3
Coarse aggregate (CA) = 1151 kg/m3
Chemical admixture (SP) = 7 kg/m3
Water cement ratio (w/c) = 0.4
8. Trial Mix ratio:
1: 2.62 : 3.33
45. 45
EXAMPLE-3(Nov/Dec 2016, Apr/May 2017)
Design of M40 grade pumpable concrete with fly ash mix as per IS:10262-2009, concrete mix
proportioning guidelines. The following are the design data’s forproportioning:
Grade designation : M40
Type of cement : OPC 43 grade confirming to IS8112
: 20 mm
: 320 kg/m3
: 0.45
: 100 mm (slump)
: Severe (for reinforced concrete)
: Pumping
: Good
: Crushed angular aggregate
: 450 kg/m3
: Superplasticizer confirming to IS9103
: 3.15
: 2.2
: 2.74
: 2.74
: 0.5 percent
: 1 percent
: Nil
: Nil
Maximum nominal size ofaggregate
Minimum cement content
Maximum water cement ratio
Workability
Exposure condition
Method of concreteplacing
Degree of supervision
Type of aggregate
Maximum cementcontent
Chemical admixture
Specific gravity of cement
Specific gravity of fly ash
Specific gravity of Coarse aggregate
Specific gravity of Fine aggregate
Water absorption:
Coarse aggregate
Fine aggregate
Free surfacemoisture:
Coarse aggregate
Fine aggregate
Sieve analysis:
Fine aggregate : Confirming to Zone I ofIS383
46. 46
EXAMPLE-3 (Cont)
Solution:
1. Target mean strength:
fckʹ = fck + 1.65 S
By referring Table 1 of IS10262:2009, S= 5
fckʹ = 40+ 1.65 x 5 = 48.25 N/mm2
2. Selection of water cement ratio:
By referring Table 5 of IS456:2000.
Adopt 0.4 < 0.45 (maximum water cement ratio for
moderate exposure)
47. 47
EXAMPLE-3 (Cont)
3. Selection of water content:
By referring Table 2 of IS 10262:2009
Water content (W) for 25mm-50mm slump is 186 litres
Water content (W) for 100 mm slump is = 186 +
6/100*186= 197 Litres
[3% water is increase for every 25 mm slump
increments]
In this mix design, superplasticizer is going to use,
hence the water content can be reduced up to 30%.
Therefore revised water content = 197 – 0.3x197 = 138
Litres.
48. 48
EXAMPLE-3 (Cont)
4. Calculation of cement content:
Water cement ratio is = 0.4
We know that, W/C = 0.4
Therefore cement content, C = W/0.4 = 138/0.4
= 345 kg/m3 > 320 kg/m3 Hence O.K.
[To add fly ash or other mineral admixture, 10% of
cement content may be added ]
The cementitious material content = 1.1x345 = 380
kg/m3
Let us use fly ash at 30%
Therefore;
Fly ash content
Cement content
= 0.3x380
= 0.7x380
= 114 kg/m3
= 266 kg/m3
49. 49
EXAMPLE-3 (Cont)
5. Volume of coarse aggregate and fine aggregate:
From Table 3 of IS10262:2009 for Zone I fine
aggregate with 20 mm sized aggregate and w/c
ratio of 0.5;
Coarse aggregate volume
correction of w/c ratio)
= 0.6+0.02 (for
= 0.62
It can be reduce to 10%, for pumpable concrete (Ref:IS10262-
2009, C-4.4.1)
= 0.9 x 0.62 = 0.56
Fine aggregate volume = 1-0.56 = 0.44
50. EXAMPLE-3 (Cont)
(a) Volume of concrete
(b) Volume of cement
= 1 m3
=
= = 0.084 m3
(c) Volume of fly ash =
= = 0.052 m3
(d) Volume of water =
= = 0.138 m3
50
51. EXAMPLE-3 (Cont)
(e) Volume of chemical admixtures (If need)
=
=
(f) Volume of aggregates (fine and coarse)
= 0.0066
= a-(b+c+d+e)
= 1-(0.084+0.054+0.138+0.0066)
= 0.71 m3
(f) Mass of coarse aggregate (CA) = f x Volume of CA x Specific gravity of
CA x 1000
= 0.71 x 0.56 x 2.74 x 1000 = 1090kg
(g) Mass of fine aggregate (FA) = f x Volume of FA x Specific gravity of
FA x 1000
= 0.71 x 0.44 x 2.74 x 1000 = 856kg
51
52. 52
EXAMPLE-3 (Cont)
7. Mix proportion for trial 1:
Cement (C) = 266 kg/m3
Fly ash (F) = 114 kg/m3
Water (W) = 138 kg/m3
Fine Aggregate (FA) = 856 kg/m3
Coarse aggregate (CA) = 1090 kg/m3
Chemical admixture (SP) = 7.6 kg/m3
Water cement ratio (w/c) = 0.4
8. Trial Mix ratio:
1: 2.25 : 2.86
