This document discusses mix proportioning of concrete. It provides information on various types and properties of concrete, factors affecting strength and workability, methods of mix design, and the general steps involved in mix proportioning. The key points are: 1) Concrete mix proportioning determines the relative amounts of ingredients to achieve the desired properties in an economical way. 2) Factors like water-cement ratio, aggregate size and grading, cement content affect the strength, workability and durability of concrete. 3) Common mix design methods include ACI, IS, and trial batch methods. The general steps are selecting slump, aggregate size, water content, water-cement ratio, and calculating cement and aggregate

1. Mix Proportioning
Dr. S. D. Bharti
Professor, Department of Civil Engineering
Malaviya National Institute of Technology Jaipur

2. Concrete
• Concrete is an artificial conglomerate stone
made essentially of Portland cement, water, and
aggregates.
• It is a Composite material that consists essentially
of a binding medium within which aggregates are
embedded
• Binder is formed from a mixture of hydraulic
cement and water.

3. Itaipu Dam, Brazil

4. Central Arizona project pipeline.
California aqueduct construction.

5. Most widely used construction material
Last year in the U.S. 63 million tons of Portland
cement were converted into 500 million tons of
concrete
Total world consumption of concrete last year is
estimated at three billion tons
Estimated present consumption of concrete in
the world is 55. billion tons every year
Concrete as a Structural
Material

6. Stat fjord B offshore concrete platform,
Norway

7. Concrete possesses excellent
resistance to water
Aqueducts and waterfront retaining walls
Dams, canal linings, and pavements
Structural elements exposed to moisture, such
as piles, foundations, footings, floors, beams,
columns, roofs, exterior walls, and pipes
Why Concrete most widely used
engineering material?

8. Hoover Dam Bypass Project

9. Ease with which structural concrete
elements can be formed into a variety of
shapes and sizes
Freshly made concrete is of a plastic
consistency
Flow into prefabricated formwork
Formwork can be removed for reuse

10. The Temple Israel was built in 1969

11. The cheapest and most readily
available material on the job
Aggregate, water, and Portland
cement are relatively inexpensive
and are commonly available
Cost may be as low as U.S. $60 to
$70 per cubic meter

12. Maintenance. Concrete does not corrode,
needs no surface treatment, and its strength
increases with time; therefore, concrete
structures require much less maintenance
Fire resistance. The fire resistance of
concrete is perhaps the most important
single aspect of offshore safety
Resistance to cyclic loading
Advantages Of Concrete

13. Based on unit weight,
Normal-weight concrete - 2400 kg/m3
Lightweight concrete - 1800 kg/m3
Heavyweight concrete - 3200 kg/m3
Based on compressive strength,
Low-strength concrete: less than 20 MPa
Moderate-strength concrete: 20 to 40 MPa
High-strength concrete: more than 40 MPa
Types of Concrete

14. Concrete is an intimate mixture of
Cement
Fine Aggregate
Coarse Aggregate
Water
Admixtures
Concrete

15. Concrete Mix Proportioning is the science of
deciding relative proportions of ingredients of
concrete, to achieve the desired properties in
the most economical way.
Mix Proportioning

16. Absolute Volume Methods
IS Method
ACI Method
Road Note No. 4 Method
DOE Method
Weight Method
USBR Method
Trial and Adjustment Method
Strands Of Proportioning

17. Weight Method
Absolute volume Method
Unit wt. of
fresh
concrete
from
experience
(Wt. of
Concrete) –
(tot. wt. of
all other,
viz water,
cement…)
Wt. of FA
(Unit vol. of
concrete)-
(vol of
water, air,
CA..)
Vol. of FA
Vol. of FA x
Density

18. METHODS OF CONCRETE MIX DESIGN
1. American Concrete Institute Committee 211 Method
 Absolute Volume Method
 Reliable
 Entrapped Air Considered
 Higher w/c Ratio
 Higher Fines content hence better Workability
2. Bureau of Indian Standards Recommended Method IS 10262-
2009
 Coarse Aggregate calculation sequence follows ACI Method
 Provision for Use of Chemical & Mineral Admixtures
 Lower Fines hence more voids
3. Road note No. 4 (Grading Curve) Method
 High Cement Content, Obsolete
 Cannot be used for Gap Graded Aggregates

19. 5. Trial and Adjustment Method
6. Department Of Environment (DOE - British) Method
7. Fineness modulus Method
8. Maximum density Method
9. Indian Road Congress, IRC 44 Method
10. USBR (United States Bureau of Reclamation) Mix
design practice

20. Its an art rather than a science
Attaining predefined requirements
Workability of fresh concrete
Placing
Compacting
Finishing
Strength of hardened concrete at a specified
age
Durability under specific exposure conditions
Freeze thaw cycles
Sulphate water
Natural agents
Significance

21. Satisfying the performance requirements
at the lowest possible cost
w/c ratio
a/c ratio
Fa/Ca ratio
Substitution of cement using pozzolanic or
cementitious materials

22. Specific Principles
Concre
te
Concre
te
Workabilit
y
Workabilit
y
Durabili
ty
Durabili
ty
Streng
th
Streng
th

23. Workability embodies consistency and
cohesiveness
Workability
Consistenc
y
Measure of wetness
of concrete (slump)
Angular & Rough texture
content
Maximum size
Air Entrained
Coal Fly Ash Content
Cohesivenes
s
Measure of
compactibility &
Finishability
Trowelability & Visual
Judgment
a/c ratio & Grading
Fa/Ca ratio

24. Water content
The higher the water content, the higher will be the
fluidity of concrete, which is one of the important
factors affecting workability.
a/c Ratio
The higher the aggregate/cement ratio, the leaner is
the concrete
In lean concrete, less quantity of paste is available for
lubrication, per unit surface area of aggregate and
hence the mobility reduced
In case of rich concrete with lower aggregate/cement
ratio, more paste is available to make the mix
cohesive and fatty to give better workability.
General Considerations for
Workability

25. Size of Aggregate
The bigger the size of the aggregate, the less
the surface area hence, less water is required
for wetting the surface and paste is required for
lubricating the surface to reduce internal
friction
For a given quantity of water and paste, bigger
size of aggregates will give higher workability
Shape of Aggregates
Angular, elongated or flaky aggregate makes the
concrete very harsh when compared to rounded
aggregates or cubical shaped aggregates
Being round in shape, the frictional resistance is
also greatly reduced

26. Surface Texture
Total surface area of rough textured aggregate is
more than the surface area of smooth rounded
aggregate of same volume
Rough textured aggregate will show poor
workability and smooth or glassy textured
aggregate will give better workability
Reduction of inter particle frictional resistance
offered by smooth aggregates also contributes to
higher workability
 Grading of Aggregates
Better the grading, the less is the void content
and higher the workability
When the total voids are less, excess paste is
available to give better lubricating effect

27. Use of Admixtures
Use of air-entraining agent being surface-
active, reduces the internal friction between the
particles
Air bubbles act as a sort of ball bearing
between the particles to slide past each other
and give easy mobility to the particles
Plasticizers and super-plasticizers greatly
improve the workability many folds

28. Strength
Structural Safety – Minimum Required
Strength to be attained
w/c
ratio
w/c
ratio
Entrain
ed Air
Entrain
ed Air
Streng
th
Streng
th

29. The strength of a material is defined as the
ability to resist stress without failure
Properties of concrete, such as
Elastic modulus,
Water tightness or impermeability, and
Resistance to weathering agents including
aggressive waters,
are believed to be dependent on strength

30. Durability
Exposure Conditions
Durability ignored for Normal Exposure
Strength- Index of general Durability
Service life of Concrete

31. Quality concrete
Better strength
Better imperviousness and durability
Dense and homogeneous concrete
Economy
Economy in cement consumption
Best use of available materials
Objectives of Mix
Proportioning

32. Aggregate comprises about 85 % volume of mass
concrete
Concrete contains aggregate upto a maximum size of
150 mm
Way particles of aggregate fit together in the mix, as
influenced by the gradation, shape, and surface texture
Grading effects workability and finishing characteristic
of fresh concrete, consequently the properties of
hardened concrete
Grading Of Aggregates

33. Good grading implies, sample of aggregates
containing all standard fractions of aggregate
in required proportion such that the sample
contains minimum voids

34. Well graded aggregate containing minimum
voids will require minimum paste to fill up the
voids in the aggregates
Minimum paste means less quantity of
cement and less quantity of water, hence
increased economy, higher strength, lower-
shrinkage and greater durability

35. Voids created by higher size filled up by
immediate next lower size
Lower size may not be accommodated in the
available gap due to small voids left out
which can reduce density
Gap Grading of Aggregates

36. Voids created by a particular size can
accommodate second or third lower size
only
For example voids created by 40mm can
accommodate 10mm & 4.75mm but not
20mm, this concept is called Gap Grading

37.  Gap graded aggregates are used
 Gap-graded mixes contain aggregate retained on a
19mm or 37.5mm sieve
 Fines passing the No. 4 sieve (4.75mm)
 Used to obtain uniform textures for exposed-
aggregate concrete
 Prone to Segregation, controlled by FA %
 Rounded aggregate used, by 25%
 Air entrainment usually is required to improve the
workability
Gap-Graded Mix

38. Increase strength and reduce creep and
shrinkage
Requirement of sand reduced by 26 to 40%
Specific area of total aggregates will be
reduced due to less sand
Requires less cement as net volume of voids
is reduced
Advantages

39. IS 456 : 2000
Code of Practice for Plain & Reinforced Concrete
Exposure Conditions
Table 5 – Minimum Cement Content & Max. w/c ratio
IS 10262: 2009
Mix Proportioning – Guidelines
Table 1 – Standard Deviation
Table 2 – Max. Water Content
Table 3 – Vol. fraction of Coarse Aggregates
IS Codes Used In Mix
Proportioning

40. IS 383 : 1970
Specifications for coarse & fine aggregates from
natural sources for concrete
Table 2 - Nominal Maximum Size
Determining Zone of Fine Aggregates
IS 2386 (Part 3): 1963
Methods of test for aggregates for concrete: Part 3.
Specific Gravity
Voids
Density
Absorption & Bulking

41. IS 3812 (Part 1) : 2003
Specification for Pulverized fuel ash: Part 1
For use of Pozzolana in cement, cement mortar and
concrete
IS 8112 : 1989
Specification for 43 grade ordinary Portland
Cement
IS 9103 : 1999
Specification for admixtures for Concrete

42. Statistical Quality Control of Concrete
Results in variation of strength from batch to
batch and also within the bat
It impossible to have a large number of
destructive tests for evaluating the strength of
the end products
The aim of quality control is to limit the
variability as much as practicable

43. By devising a proper sampling plan it is possible to
ensure a certain quality at a specified risk
Extent of variation of strength can be ascertained
by relating the individual strength to the mean
strength and determining the variation from the
mean with the help of the properties of the normal
distribution curve

44. Compressive strength
Workability
Durability
Maximum nominal size of aggregate
Fineness Modulus and zone of aggregate
Quality Control
Factors affecting the choice of
mix proportions

45. Water Cement Ratio
Strength Criteria
Durability Criteria
Durability decreases with increase in w/c ratio
Higher is the aggressiveness of the environment lower
should be the w/c ratio
Significance of Max. w/c Ratio &
Min. Cement Content
Higher
w/c
ratio
Increased
Permeability
Volume
Change
Cracking
Disintegrati
on and
Failure

46. • Strength of paste increases with cement content and
decreases with air and water content

47. Studies show that,
Capillary porous start to be connected when w/c
is higher than 0.40
When w/c is higher than 0.70, all capillary porous
are connected
Hence,
The maximum value for w/c ratio is 0.70
Concrete exposed to a very aggressive
environment the w/c should be lower that 0.40

48. Effect of Solid/Space Ratio &
Permeability On Compressive
Strength

49. Advantages of low water-cement ratio:
o Finer microstructure
o Low chloride ion diffusion
o Corrosion resistance
o Low susceptibility to carbonation,
electrochemical attack

50. Step 1. Choice of Slump
Stiffest possible consistency that can be easily
placed and compacted without segregation
Pumping are typically designed for 100 mm to
150 mm slump
General Steps Involved in Mix
Proportioning

51. Step 2. Choice of Max. Size of Aggregate
For given volume of coarse aggregate,
Large Max.
Size (well
graded)
Less void
Space
Reduce
mortar
requirement

52. Step 3. Estimation of the mixing water content
and air content
Depends on ,
The maximum particle size of the aggregate
Entrained air

53. Step 4. Selection of water-cement ratio
Develop the relationship between strength
and water-cement ratio for the materials to
be used actually
Checked for durability criteria

54. Step 5: Calculation of the cement content
Computed by dividing the mixing water content
by the water-cement ratio
Adjustments to Min. cement content for
aggregates other than 20 mm nominal max.
size, as per IS 456: 2000

55. • Step 6: Estimation of the coarse aggregate
content
• Estimated from Maximum aggregate size &
fineness modulus of fine aggregate
• Dry weight obtained by multiplying with Dry
Rodded unit weight

56. Range in proportions of materials used in
concrete, by absolute volume

57. Step 7: Estimation of the fine aggregate
content
Weight Method
Absolute volume Method

58. Step 8: Adjustments for the aggregate
moisture
Mixing water reduced depending on Free
Moisture
Amounts of aggregates increased accordingly
Step 9: Trial batch adjustments
Mixture satisfying the desired criteria of
workability and strength is obtained
Mixture proportions of the laboratory-size trial
batch are scaled up for producing full-size field
batches

59. Basic factors in the process of Mix Design
Liability to chemical
attack or size of concrete mass
Method
Of
Compaction
Size of section
and spacing
of Reinforcement
Minimum
Strength
Maximum
Size of
Aggregate
Aggregate
Shape and
Texture
Quality
Control
Mean
Strength
Type
of
Cement
Age at
which Strength
is required
Required
Workability
Durability
Water/Cement
Ratio
Aggregate/Cement
Ratio
Overall
Grading of
Aggregate
Proportion
of each Size
Fraction
Mix ProportionsCapacity
of the Mixer
Weights of Ingredients
Per Batch

60. Grade Designation
Type of Cement
Maximum Nominal size of Aggregate
Minimum Cement Content
Maximum w/c ratio
Workability in terms of Slump
Data required for
Proportioning

61. Exposure conditions
Method of placing
Type of aggregate
Maximum cement content
Test data of Materials
Admixture type and condition of use if any

62. Mix Proportioning
Target Strength
Selection of w/c Ratio
Selection of Water content
Check for
max w/c
Correction
for Slump
Admixture
Correction(if
any)
Calculation Of Cement
Content
Check for
Min.
Cement
Proportion Of CA & FA
Correction
for w/c
Correction for
Placement
Type
Mix Calculations

63. Comparison Basic data used in
the Old and New BIS Methods

64. Target strength for mix proportioning
Selection of w/ c ratio
Selection of water content
Corrections in water content
Mix Proportioning Procedure

65. Calculation of cement content
Proportion of volume of coarse aggregate and
fine aggregate content
Corrections
Mix calculations

66. Design stipulations for proportioning
Grade designation : M20
Type of cement : OPC 43 grade, IS 8112
Max. nominal size of agg. : 20 mm
Minimum cement content : 320 kg/m3
Maximum water cement ratio : 0.55
Numerical Example

67. Workability : 75 mm (slump)
Exposure condition : Mild
Degree of supervision : Good
Type of agg. : Crushed angular agg.
 Maximum cement content : 450 kg/m3
Chemical admixture : Not used

68. Test data for materials
Cement used : OPC 43 grade
Specific gravity of cement : 3.15
Specific gravity of
Coarse aggregate : 2.68
Fine aggregate : 2.65
Water absorption
Coarse aggregate : 0.6 percent
Fine aggregate :1.0 %

69. Free (surface) moisture
Coarse aggregate : Nil
Fine aggregate : Nil
Sieve analysis
Coarse aggregate : Conforming to Table 2 of IS
383
Fine aggregate : Conforming to Zone I of IS 383

70. Target strength =
f’ck= fck +ks
From Table 1
standard deviation, s
= 4 N/mm2
Therefore target strength
= 20+1.65 x4
= 26.60 N/mm2
1. Target strength for Mix Proportioning

71. From Table 5 of IS 456:2000,
Maximum w/c ratio = 0.55 (Mild exposure)
Based on experience adopt water cement ratio as
0.50
0.5 < 0.55, hence ok
2. Selection of w/ c ratio

72. 3. Selection of water content
From Table 2, IS 10262:2009
Maximum water content = 186 litres
(for 25mm – 50 mm slump range and for 20 mm aggregates)

73. As per IS10262:2009 Clause 4.2,
For workability other than 25-50mm the
required water content can be established by
trial or increasing 3% for every additional
25mm slump and considering correction for
admixture if any.
Estimated water content for 75 mm slump
= 186 + 3/100 x 186
= 191.6 litres
4.Corrections in Water content

74. Water cement ratio = 0.50
Cement content = 191.6/0.5
= 383 kg/m3 >320 kg/m3(given)
5.Calculation of cement content

75. From Table 5 of IS 456,
Minimum cement content for mild exposure
condition
= 300 kg/m3, Hence OK

76. From Table 3, IS 10262:2009
Volume of coarse aggregate corresponding to
20 mm size aggregate and fine aggregate
(Zone I) for water-cement ratio of 0.50
= 0.60
6.Proportion of volume of Coarse
aggregate and Fine aggregate content

77. 7.Mix calculations
The mix calculations per unit volume of concrete shall be as
follows
1) Volume of concrete = 1 m3
2) Volume of cement = mass of cement/sp. gravity of cement
x 1/1000
= [383.16/3.15] x [1/1000]
= 0.122 m3
3) Volume of water = [192/1] x [1/1000]
= 0.192 m3

78. 4)Volume of all in aggregates (e) = a – (b + c)
= 1 – (0.122 + 0.192)
= 0.686 m3
5) Volume and weight of coarse aggregates
Volume = 0.686 x 0.6 = 0.412 m3
Weight = Volume of CA (0.412 m3) x sp. gravity(2.68) of CA =
1103 kg
6) Volume and weight of fine aggregates
= e x Volume of FA (0.274 m3) x sp. gravity of FA
Volume = 0.686 x 0.4 = 0.274 m3
Weight = Vol. of FA (0.274 m3) x sp. gravity(2.65) of FA x 1000
= 727 kg

79. 8.Mix proportions for Trial Number 1
Cement = 383 kg/m3
Water = 191.6 kg/m3
Fine aggregate = 727 kg/m3
Coarse aggregates = 1103 kg/m3
Water cement ratio = 0.50
Yield = 2404.6 kg

80. Questions??