The process of selecting suitable ingredients of concrete and determining their relative amounts with the objective of producing a concrete of the required, strength, durability, and workability as economically as possible, is termed the concrete mix design.

1. DESIGN OF CONCRETE LAKSHMI RAVI
CHANDU KOLUSU

2. OBJECTIVES OF MIX DESIGN
To find a combination of constituents that would give concrete of
properties complying with certain specifications economically.
Properties are selected depending on the application and
expected performance.

3. WHAT IS MIX DESIGN??
The process of selecting suitable ingredients of concrete and
determining their relative amounts with the objective of producing a
concrete of the required strength, durability, and workability as
economically as possible, is termed the concrete mix design

4. TYPE OF MIXES
Nominal Mix:
 The mixes of fixed cement-aggregate ratio which ensures adequate strength are
termed nominal mixes.
 These mixes offer simplicity and under normal circumstances, gives a specified
marginal strength.
 But variability of mix ingredients causes variation in strength.

5. TYPE OF MIXES
Standard mix:
 The nominal mixes of fixed cement-aggregate ratio (by volume) vary widely in
strength and may result in under- or over-rich mixes.
 Those mixes which ensure a minimum compressive strength are known as standard
mixes.
 IS 456-2000 has designated the concrete mixes into a number of grades as
M10, M15, M20, M25, M30, M35 and M40

6. TYPE OF MIXES
Standard mix
 M- mix
 Number- 28 day characteristic compressive strength in MPa.
Grade of Concrete Mixproportion
M10 1:3:6
M15 1:2:4
M20 1:1.5:3
M25 1:1:2

7. TYPE OF MIXES
Design Mix:
 Most rational approach to the selection of mix proportions
 This approach results in the production of concrete with the
appropriate properties most economically

8. FACTORS AFFECTING MIX
DESIGNCompressive Strength
 Most important property
 Influences many other properties of concrete
Workability
 Degree of workability required depends on:
 Size of section
 Amount of reinforcement
 Amount of compaction

9. RECOMMENDED SLUMP
VALUES
(IS 456:2000)
Use Slump value
Shallow section Very low
Mass concrete, lightly reinforced
beam
25-75
Heavily reinforced beam 50-100
Pumped concrete, tremie concrete 100-150

10. FACTORS AFFECTING MIX
DESIGNDurability:
 High strength concrete more durable than low strength concrete.
 Depends on exposure conditions.
Maximum nominal size of aggregate
 Larger aggregate size -higher workability
 Higher aggregate size-low strength.

11. FACTORS AFFECTING MIX
DESIGNGrading and type of aggregate
 Type of aggregate influences aggregate cement ratio.
Quality control
 Degree of control can be estimated by studying variation in test results.

12. METHODS OF MIX
PROPORTIONING Arbitrary proportion
 Fineness modulus method
 Maximum density method
 Surface area method
 Indian Roads congress ,(IRC 44 method.
 High strength concrete mix design
 Road note No.4 method (Grading Curve Method)
 ACI committee 211 method
 DOE method
 Mix design for pumpable concrete
 Indian Standard Recommended Method IS 10262:2009

13. ACI METHOD
Introduced in 1944- later revised to include air entraining
agents in 1954.
1970- developed as a standard method of concrete mix
design- ACI 211.1 of 1991

14. ACI 211.1 OF 1991
Assumptions :
 Fresh concrete of given slump and containing well graded aggregate
will have a practically constant total water content ( regardless of
variations in w/c ratio and cement content).
 Dry volume of coarse aggregate per unit volume of concrete depends
on its maximum size and fineness modulus of the fine aggregate.
 Irrespective of the compaction, a defnite % of air remains which is
inversely proportional to maximum size of aggregate.

15. IS METHOD( IS 10262: 2009)
Introduced in the year 1982.
Later modified to confirm with the requirements of IS
456:2000

16. DATA FOR MIX
PROPORTIONING
Grade designation
Type of cement
Maximum nominal size of aggregate.
Minimum cement content.
Maximum water-cement ratio.
Workability.

17. DATA FOR MIX
PROPORTIONING
Exposure conditions as per Table 4 and Table 5 of IS
456.
Maximum temperature of concrete at the time of placing.
Method of Transporting and placing.
Early age strength requirements, if required.
Type of aggregate.
Maximum cement content.
Whether admixture used or not.

18. IS METHOD( IS 10262: 2009)
1. Target Mean Strength
 Concrete mix is designed for certain higher strength than characteristic
strength.
 f’ck = fck + 1.65 σ
f’ck= target mean strength at 28 days in N/mm^2
fck = characteristic compressive strength at 28 days in N/mm^2 .
σ = standard deviation in N/mm^2.

19. CALCULATION OF STANDARD
DEVIATION(a) Standard deviation based on test strength of
sample
 The total number of test strength of samples
required to constitute an acceptable record for
calculation of standard deviation shall be not less
than 30.

20. CALCULATION OF STANDARD
DEVIATION
(b) Standard deviation from Table 1 of IS
10262:2009Grade of Concrete Assumed Standard
deviation(Mpa)
M10, M15 3.5
M20, M25 4.0
M30 and above 5.0
Note: Above values correspond to the site control having proper
storage of cement; weigh batching of all materials; controlled
addition of water, regular checking of all materials. aggregate
grading and moisture content; and periodical checking of
workability and strength. Where there is deviation from the above,
values given in the above table shall be increased by 1 N/mm2

21. 2. SELECTION OF WATER
CEMENT RATIO
 Water cement ratio selected based on laboratory or site trials.
 Relationship between free water cement ratio and 28 day strength should be
established for the actual materials used.
 Not possible always due to lack of data and time.

22. RELATION BETWEEN W/C RATIO AND
COMPRESSIVE STRENGTH AS PER IS
456:2000

23. As per IS
10262:1982,
w/c ratio is selected
from ABCDEF
curves relating
strength of
concrete and w/c
ratio.

24. 2. SELECTION OF WATER
CEMENT RATIO:
 w/c ratio selected should be checked against limiting w/c ratio for durability(
from Table 5 of IS 456:2000)
 Lower of two values should be adopted

25. TABLE 5 OF IS 456

26. 3. SELECTION OF WATER
CONTENT
 The quantity of maximum mixing water per unit volume of concrete
may be determined from Table 2 of IS 10262:2009.
 For angular aggregate and 25 – 50 mm slump range.
Nominal maximum size of
aggregate(mm)
Maximum water content
(kg)
10 208
20 186
40 165

27. 3. SELECTION OF WATER CONTENT
Water content should be increased by 3% for
every additional 25 mm slump.
Modification of water content for aggregates
other than angular.
Reduce water content by 5 to 10% for
plasticizers and by 20 % for superplasticizers.
Type of aggregate Water content reduced by( kg)
Sub angular 10
Gravel with some crushed
particles
20
Rounded gravel 25

28. 4. CALCULATION OF CEMENT
CONTENT
 The cement and supplementary cementitious material content per unit volume of
concrete may be calculated
 from the free water-cement ratio
 quantity of water per unit volume of concrete.
 The cement content so calculated shall be checked against the minimum content
for the requirements of durability(IS 456:2000)
 Greater of the two values should be adopted.

29. TABLE 5 OF IS 456

30. 5. ESTIMATION OF COARSE
AGGREGATE PROPORTION
Nominal
maximum
size of
aggregate
Volume of coarse aggregate per unit volume of total
aggregate for different zones of fine aggregate for w/c
ratio of 0.5
Zone IV Zone III Zone II Zone I
10 0.50 0.48 0.46 0.44
20 0.66 0.64 0.62 0.60
40 0.75 0.73 0.71 0.69

31. 5. ESTIMATION OF COARSE
AGGREGATE PROPORTION
Volume of coarse aggregate is modified by -/+ 0.01 for
every +/- 0.05 change in water cement ratio.

32. 6.ESTIMATE OF FINE
AGGREGATE FRACTION
Proportion of all other ingredients except CA
and FA is determined.
Find out the total aggregate volume for 1
cubic meter of concrete.
From this amount of fine aggregate is found
out.