Chapter 2
Concrete Mix Design
• ProQuest Reference book :
• Handbook on Advanced Concrete Technology, edited by N.V. Nayak, and
A.K. Jain, Alpha Science International, 2012. ProQuest Ebook Central,
• Design of Normal concrete Mixes (Building Research Establishment,
walford, U.K, 1988
• Open Source book: Concrete Technology by Shetty. M.S .
• ProQuest Ref. Link :
https://ebookcentral.proquest.com/lib/momp/reader.action?docID=5334822
&ppg=116
• Masader Reference Link:
https://www.masader.om/eds/detail?db=aci&an=118760371&isbn=1687843
4
About
Concrete
• Concrete is the second
largest material consumed
by human beings after
food and water as per
WHO.
https://gcpat.in/en-gb/news/blog/using-right-concrete-mix
Concrete Mix design
• Concrete Mix design can
be defined as the process
of selecting suitable
ingredients
of concrete and
determining their relative
proportions with the object
of producing concrete of
certain minimum strength
and durability as
economically as possible.
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Requirements of
concrete mix design
Required,
• Minimum compressive
strength
• Adequate workability
• Maximum watercement ratio
• Maximum cement
content
Types of Concrete Mix Design
• 1. Nominal Mixes –
• These mixes are of fixed cementaggregate ratio.
• These offer simplicity and under
normal circumstances.
• Have a margin of strength above
that specified.
• 2. Standard Mixes –
• The minimum compressive
strength has been included. These
mixes are termed standard mixes.
• https://www.youtube.com/watch?v=xpBtzdj0Ie0
• E.g.: M10, M15, M20, etc.
Cont….
3. Designed Mixes –
• In these mixes the performance of the concrete is specified
by the designer but the mix proportions are determined by
the producer of concrete, except that the minimum cement
content can be laid down.
DOE Method (British standard Method BS8110)
Methods of
Concrete
Mix Design
American Concrete Institute Method (ACI
Method)
• Road Note Number 4 Method
• Indian Standard Method (IS Method)
Trial & Error Method
DOE Method
• The DOE method was first
published in 1975 and then
revised in 1988.
• While Road Note No 4 or
Grading Curve Method was
specifically developed for
concrete pavements, the DOE
method is applicable to
concrete for most purposes,
including roads.
• DOE method is the standard
British method of concrete
mix design, the procedure
involved in this method is
described instead of out dated
Road Note No 4 method.
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Mix Design
(BS 1800)
DATA
REQUIRED
a)
Grade Designation
b)
Type of cement
c)
Size of Aggregate
d)
Maximum water-cement ratio
e)
Workability: Slump
f)
Type of Aggregate
g)
Whether an admixture shall or shall not be used
Procedure for Concrete Mix Design – DOE Method
Step 1
Target Mean compressive Strength
Step 2
Water/Cement ratio.
Step 3
Water content
Step 4
Cement content
Step 5
Weight of Total Aggregate
Step 6
Weight of Fine Aggregate & Coarse Aggregate
Step 7
Proportions ( Cement : F.A : C.A : w/c )
1.
2.
3.
4.
5.
Characteristic compressive strength 30 N/mm2 at 28 days
Cement: OPC class 42.5
Slump required, 75 mm
Maximum free-water/Cement ratio 0.55
Coarse aggregate: Uncrushed single sized 10 mm and 20 mm
(1:2 by weight)
6. Fine aggregate: Uncrushed with 70% passing 600 μm sieve
7. Specific gravity (Relative density) of coarse aggregate : 2.65
8. Specific gravity (Relative density) of fine aggregate : 2.61
9. Volume of trial mix : 0.05 m3
10. Consider Field conditions also.
Design a concrete mix
for construction of an
elevated water tank.
The specified design
strength of concrete
(characteristic
strength) is 30 Mpa at
28 days cube strength
from the following
data:
Solution:
Step 1: Target Mean Strength (fm)
Find the target mean strength from the specified characteristic strength
 (risk factor or defective level is on the assumption that 5 percent of results are allowed to fall less than the
specified characteristic strength). Refer page 12 figure.3
𝑓𝑚= fs + k x S
From BS code book
𝑓𝑚=30 + 1.64 𝑥 8.0
𝑓𝑚=43.12 𝑀𝑃𝑎
Step 02: Water/cement ratio
Referring to Table 2 & figure.4 page no.12 for OPC,
uncrushed aggregate, for W/C ratio of 0.5, 28 days
compressive strength is 42 MPa. Draw a dotted line curve
parallel to the neighboring curve. From this curve read off the
W/C ratio for a target mean strength of 43.12 MPa.
The Water/cement ratio is = 0.48
Given, maximum W/C ratio is 0.55.
Adopt lower of the two
Therefore adopt W/C ratio of 0.48
• Step 03: Calculation
of Water Content
• Next decide the
water content for
slump of 75 mm 20
mm uncrushed
aggregate from Table
11.12.
• Water demand for
Uncrushed
(natural)aggregate =
195 lit
• Step 05: Cement Content
• Mixing water content is 195 kg/m3
of concrete.
• w/c = 0.48
• 195/c = 0.48
• 𝐶𝑒𝑚𝑒𝑛𝑡 𝐶𝑜𝑛𝑡𝑒𝑛𝑡 (c )=406.25 𝑘𝑔/𝑚
3
•
•
•
•
•
•
Minimum Cement content = 325 kg
(As per Table No. 9.2 of
BS 8110 : Part I : 1985 )
Select whichever is maximum
Say,
Cement content = 406.25 kg/m3
Step 06: Weight of Total Aggregate
 To
find out the density of fresh concrete from
Fig. 5, Page no.14 for water content of 195 kg/m3, 20 mm
uncrushed aggregate of sp.gr. 2.65
The 𝑤𝑒𝑡 𝑑𝑒𝑛𝑠𝑖𝑡𝑦 = 2395.0 𝑘𝑔𝑚3
𝑊𝑒𝑖𝑔h𝑡 𝑜𝑓 𝑇𝑜𝑡𝑎𝑙 𝐴𝑔𝑔𝑟𝑒𝑔𝑎𝑡𝑒 =𝑇h𝑒 𝑤𝑒𝑡 𝑑𝑒𝑛𝑠𝑖𝑡𝑦−(𝑊𝑒𝑖𝑔h𝑡 𝑜𝑓 𝐶𝑒𝑚𝑒𝑛𝑡 content + 𝑊𝑒𝑖𝑔h𝑡 𝑜𝑓 water content)
𝑊𝑒𝑖𝑔h𝑡 𝑜𝑓 𝑇𝑜𝑡𝑎𝑙 𝐴𝑔𝑔𝑟𝑒𝑔𝑎𝑡𝑒=2395 − (406.25 + 195) = 1793.75 kg/m3
Step 07: Weight of Fine Aggregate & Coarse Aggregate
Then, proportion
of fine aggregate is determined in the total aggregate using Fig. 6 is for 10 mm size, 20 mm size and
40 mm size coarse aggregate.
The
parameters involved are maximum size of coarse aggregate, the level of workability, the water/cement ratio, and
the percentage of fine passing 600 μ seive.
For
20 mm aggregate size, W/C ratio of 0.48, Slump of 75 mm, for 70% fines passing through 600 μ sieve, the
percentage of
% 𝐹𝑖𝑛𝑒 𝐴𝑔𝑔𝑟𝑒𝑔𝑎𝑡𝑒 =34 % (From fig.6, 20 mm size)
𝑊𝑒𝑖𝑔h𝑡 𝑜𝑓 𝐹 𝐴.=1793.75 × 0.34 = 609.875 𝑘𝑔/𝑚3
And
𝑊𝑒𝑖𝑔h𝑡 𝑜𝑓 𝐶 𝐴.=1793.75 – 609.875 =1183.875 𝑘𝑔/𝑚3
Maximum aggregate size :
10 mm
• Figure 6 Recommended
proportions of fine aggregate
according to percentage
passing a 600 μm sieve
Figure 6 Recommended proportions of fine aggregate according to percentage passing a 600 μm sieve
• Figure 6 Recommended
proportions of fine
aggregate according to
percentage passing a 600
μm sieve
Step 09: Proportions
Ingredients
Cement
Fine
Aggregate
Coarse
Aggregate
Water
Chemical
Quantity 𝑘𝑔/𝑚3
406.25
609.875
1183.875
195.0
NM
Ratio
1.00
1.5
2.914
0.48
NM
Step 09: Proportions
Ingredients
Cement
Fine Aggregate
Quantity 𝑘𝑔/𝑚3
406.25
609.875
Coarse
Aggregate
1183.875
Water
Chemical
195.0
NM
0.48
24.0
9.75
NM
NM
NM
(394.625 for 10mm & 789.25
for 20 mm)
Ratio
1 Bag Cement
Quantity –
0.05m3
1.00
50.0
20.3
1.5
75.0
30.49
2.914
145.7
59.19
Step 10: Adjustment for Field Condition
The proportions are required to be adjusted for the field
conditions.
Fine Aggregate has surface moisture of 2 %
Weight of F. A. = 609.875 + (0.02 x 609.875)
= 622.07 kg/m3
≅ 625 kg/m3
Course Aggregate absorbs 1% water
Weight of C. A. =1183.875 – (0.01 x 1183.875)
= 1172.04 kg/m3
≅ 1175 kg/m3
Step 10: Final Design Proportions
Ingredients
Cement
Fine Aggregate
Coarse
Aggregate
Water
Chemical
Quantity 𝑘𝑔𝑚3
406.25
625.0
1175
195
NM
(391.67 for 10mm & 783.33
for 20 mm)
Ratio
1.00
1.538
2.89
0.48
NM
1 Bag Cement
50.0
90.0
125.5
25.0
NM
Quantity – 0.05m3
20.3
31.25
58.75
9.75
NM
Example problems for Practice
2. Design a concrete mix for M25 grade of concrete using BS Method with
the following data:
1. Type of Cement: OPC class 42.5
2. Defective rate : 2.5%.
3. Slump required, 75 mm
4. Maximum free-water/Cement ratio 0.50
5. Minimum cement content : 320 Kg/m3
6. Coarse aggregate: Crushed Angular Aggregate
7. Fine aggregate: Uncrushed with 50% passing 600 μm sieve
8. Specific gravity (Relative density) of coarse aggregate : 2.80
9. Specific gravity (Relative density) of fine aggregate : 2.70
3. Design a concrete mix for M40 grade of concrete using BS Method with the following
data:
1. Type of Cement: OPC class 52.5
2. Slump required, 10-30 mm
3. Maximum free-water/Cement ratio 0.55
4. Type of aggregate: Crushed with 50% passing 600 μm sieve
5. Specific gravity (Relative density) of coarse aggregate : 2.80
6. Specific gravity (Relative density) of fine aggregate : 2.70
4. Design a concrete mix for a reinforced concrete work which will be
exposed to the moderate condition. The concrete is to be designed for a
mean compressive strength of 40 Mpa at the age of 28 days. A
requirement of 25 mm cover is prescribed. Maximum size of aggregate is
20 mm uncrushed aggregate will be used. Sieve analysis shows that 50%
passes through 600μ sieve. The water content for slump of 10 - 30 mm.
The bulk specific gravity of aggregate is found to be 2.65. Take defective
rate as 2.5%. The cement is replaced by Red mud (mineral Admixture) by
20%. Also Superplasticizer is added by 2 % of concrete.
Concrete Mix Design IS 10262:2009
Design a concrete mix by IS method for the following requirements:
Characteristic compressive strength at 28 days - 30 N/mm2
Max. nominal size of aggregate
- 20 mm
Shape of aggregate
- angular
Degree of workability, slump of concrete
- 100mm
Type of Exposure
- Mild
Test data for concrete making materials:
specific gravity of cement – 3.15
specific gravity of C.A
– 2.7
specific gravity of F.A
– 2.6
water absorption of C.A
- 0.5 %
water absorption of F.A
-1%
Solution:
Step 1: Target Mean Strength (ft)
Find the target mean strength from the specified characteristic strength
 (risk factor or defective level is on the assumption that 5 percent of results are allowed to fall less than the
specified characteristic strength). Refer Table.1,
 𝑓t= fck + k x S
From IS 10262 code book
𝑓t=30 + 1.65 𝑥 5.0
𝑓t= 38.25 𝑀𝑃𝑎
Step 02: Water/cement ratio
Considering moderate exposure, Max w/c = 0.5
Hence w/c = 0.38
Choose lowest one
Say,
w/c = 0.38
Step 03: Calculation of Water Content
20
mm size aggregate from Table 2
Water
Content = 186 lit
As per IS 10262-2009
Slump is 25to 50mm, increase by 3 % for every
additional slump of 25mm.
Slump = 100 mm
Correct Water Content for 100 mm slump = 186 + 6% = 197.16 kg/m3
Step 05: Cement Content
Mixing
water content is 186 kg/m3 of concrete.
w/c = 0.38
197.16/c = 0.38
𝐶𝑒𝑚𝑒𝑛𝑡 𝐶𝑜𝑛𝑡𝑒𝑛𝑡 (c )=518.42 𝑘𝑔/𝑚3
Minimum Cement content = 300 kg/m3
(As per Table No. 5 , IS 456)
Select whichever is maximum
Say,
Cement content = 518.42 kg/m3
Step 06: Weight of Total Aggregate
From table 3,(IS-10262:2009) for zone IIIrd of F.A.
Maximum size of aggregate = 20 mm.
Vol. of CA per unit vol. of total aggregate = 0.64
Total aggregate = 1
CA = 0.64 m3
FA = 0.36 m3
Step 07: Weight of Fine Aggregate & Coarse Aggregate
Find
out the absolute volume of cementitious material, water and chemical admixture by dividing their masses by their
respective specific gravity and multiplying by 1/1000.
Quantities by volume
• Cement—518.42/(3.15 x 1000)=.165 cum
• Water ----197/(1 x 1000)=.197cum
• Total Aggregates -----1 - (.165+.197)=.638 cum
• CA------------- 0.638 x 0.664= 0.4236cum
• FA---------------- 0.638 x 0.336= 0.214 cum
Quantities by Mass
• Cement-----518.42 kg
• Water ----------197 kg
• CA--------------.4236*2.74*1000=1161.76kg
• FA------------.214*2.74*1000=586.36 kg
Step 09: Mix Proportions
Ingredients
Cement
Fine Aggregate Coarse
Aggregate
Water
Chemical
Quantity 𝑘𝑔/𝑚3 518.42
197
586.36
197.0
NM
Ratio
1.13
2.24
0.38
NM
1.00
Exercise Questions
1. Write the name of Superplasticizer commonly used in Oman
2. Write the ratio of concrete commonly used.
References
• Design of Normal concrete Mixes (Building Research Establishment,
walford, U.K, 1988
• Mix Design 10262-2009