Numerical problem on concrete mix design by is 10262(2009) method

Subject: Concrete Technology
Numerical Problem on Concrete Mix
Design by IS:10262(2009) method
by
Dnyaneshwar. D. MoreDnyaneshwar. D. More
(Assistant Professor)
DEPARTMENT OF CIVIL ENGINEERING
Sanjivani Rural Education Society’s
SANJIVANI COLLEGE OF ENGINEERING, KOPARGAON – 423 603
SAVITRIBAI PHULE PUNE UNIVERSITY, PUNE

Problem
Design of M25 grade concrete mix as per IS:10262-
2009, Concrete mix proportioning guidelines
1. Design Stipulations For Proportioning
i. Grade designation : M25
ii. Type of cement : OPC 43 grade confirming to IS 8112ii. Type of cement : OPC 43 grade confirming to IS 8112
iii. Maximum nominal size of C.A. : 20 mm
iv. Minimum cement content : 320 Kg/m3
v. Maximum water cement ratio : 0.55
vi. Workability : 75 mm (slump)

vii. Exposure condition : Mild
viii. Degree of supervision : Good
ix. Type of aggregate : Crushed angular aggregate
x. Maximum cement content : 450 kg/m3
xi. Chemical admixture : Not recommended
2. Test Data For Materials2. Test Data For Materials
p) Cement used : OPC 43 grade confirming to IS 8112
q) Specific gravity of cement : 3.15
r) Specific gravity of (SSD Condition):
i. Coarse aggregate : 2.68
ii. Fine aggregate : 2.65

s) Water absorption:
i. Coarse aggregate : 0.6 percent
ii. Fine aggregate : 1.0 percent
t) Free (surface) moisture:
i. Coarse aggregate : Nili. Coarse aggregate : Nil
ii. Fine aggregate : Nil
u) Sieve analysis result (Conforming IS: 383)
i. Coarse aggregate : Table 2 of IS: 383
ii. Fine aggregate : Zone I of IS: 383

3.Target Strength For Mix Proportioning
Fck = fck + 1.65 x S
Where,
Fck = Target average compressive strength at 28 days,
fck = Characteristic compressive strength at 28 days,fck = Characteristic compressive strength at 28 days,
S= Standard deviation
From Table 1 standard deviation, S = 4 N/mm2
Therefore, Target strength,
Fck = 25 + 1.65 x 4 = 31.60 N/mm2

4. Selection of Water Cement Ratio
From Table 5 of IS:456-2000, maximum water cement
ratio = 0.55 (Mild exposure),
adopt water cement ratio as 0.50.
So, 0.5 < 0.55, hence ok.
5. Selection of Water Content5. Selection of Water Content
From Table-2, IS:10262, maximum water content =
186 liters (for 25mm to 50mm slump range and for 20
mm aggregates)
Estimated water content for 75 mm slump = 186
+ 3/100 x186 = 191.6 liters

6. Calculation of Cement Content
Water cement ratio = 0.50
Cement content = W.C./w-c ratio=191.6/0.5=383 kg/m3 i.e.
> 320 kg/m3 also, mini. cement content as per Table 5 of
IS: 456 for mild exposure condition =300 kg/m3 and
also < 450 kg/m3 Hence, Ok.
7. Proportion of Volume of Coarse Aggregate and Fine7. Proportion of Volume of Coarse Aggregate and Fine
Aggregate Content:
From Table 3, of IS:10262 corresponding to 20 mm size
aggregate and fine aggregate (Zone I) for water-cement
ratio of 0.50
volume of coarse aggregate =0.60

8. Mix Calculations
The mix calculations per unit volume of concrete shall
be as:
a) Volume of concrete = 1 m3
b) Volume of cement =[383.16/3.15] x [1/1000]
3= 0.122 m3
c) Volume of water = [192/1] x [1/1000] = 0.192 m3
d) Volume of all in aggregates =(a) – (b) – (c)
= 1 – 0.122 – 0.192
= 0.686 m3

e) Mass of coarse
aggregates = (d) x Volume of CA x sp. gravity of CA
= 0.686 x 0.6 x 2.68 x 1000
= 1103 kg
f) Mass off) Mass of
fine aggregates = (d) x Vol. of FA x sp. gravity of FA
= 0.686 x 0.4 x 2.65 x 1000
= 727 kg

9. Estimated quantities for Trial Mix 1 (SSD Condition)
Cement = 383 kg/m3
Water = 191.6 kg/m3
Fine aggregate = 727 kg/m3
Coarse aggregates = 1103 kg/m3
Water cement ratio = 0.50Water cement ratio = 0.50
Yield =(383+191.6+727+1103)=2404.6 kg/m3
10.Mix Proportions For Trial Number 1 (SSD)
w/c=0.50; Cement :Fine Agg. :Coarse agg.
1 : 1.89 : 2.88

11. Correction for free surface moisture and water
absorption (Aggregates other than SSD):
 As per IS:10262 aggregates shall be used in SSD condition.
 If no, allowance shall be made for the free (surface)
moisture contributed by the fine and coarse aggregates.
 if the aggregates are dry, the amount of mixing water shall
be increased by an amount equal to the moisture likely tobe increased by an amount equal to the moisture likely to
be absorbed by the aggregates.
 Necessary adjustments are also required to be made in
mass of aggregates.
 Provided the surface water and percentage water
absorption of aggregates shall be determined according to
IS 2386 after that the will be check by trial mix / batches.

Correction for free surface moisture and water absorption
(Aggregates other than SSD):
(In our case the coarse and fine aggregates are in dry condition as
water absorption is given)
a) Fine Aggregate (Dry) = (Mass of SSD F.A.) / {1+((water absorp. by F.A.)/100)}
= 727 /{1+((1)/100)}
= 719.802 kg/m3
b) Coarse Aggregate (Dry) = (Mass of SSD C.A.) /{1+((water absorp. C.A.)/100)}b) Coarse Aggregate (Dry) = (Mass of SSD C.A.) /{1+((water absorp. C.A.)/100)}
= 1103 /{1+((0.6)/100)}
=1096.42 kg/m3
c) The extra water to be added for absorption:
Fine Aggregate = (Mass of FA in SSD condition – Mass of FA in dry condition)
= 727 – 719.802
= 7.2 kg
coarse Aggregate = (Mass of CA in SSD condition – Mass of CA in dry condition)
= 1103 – 1096.42
= 6.58 kg

c) The extra water to be added
for absorption = water absorbed by F.A. + water absorbed by C.A.
= 7.2 + 6.58
= 13.78 kg
Estimated water content will be = water content before correction + water
to be added for absorption
= 191.6+13.78
= 205.38 kg
12. Final Estimated quantities : For Trial mix Number 112. Final Estimated quantities : For Trial mix Number 1
Cement = 383 kg/m3
Water = 205.38 kg/m3
Fine aggregate = 719.802 kg/m3
Coarse aggregates = 1096.42 kg/m3
Water cement ratio = 0.536
Yield =(383+205.38+719.802+1096.42)= 2404.602kg/m3

13. Final Mix Proportions For Trial Number 1 (SSD)
w/c=0.536;
Cement :Fine Agg. :Coarse agg.
1 : 1.879 : 2.863
Trial Batches or Mixes:
 The calculated mix proportions shall be checked by The calculated mix proportions shall be checked by
means of trial batches.
 Quantity of concrete (materials) for each trial shall
be enough for casting at least three 150 mm size
cubes and to carry out workability test according to
IS: 1199.

 Trial Mix 1: should be checked for workability and
freedom from segregation and Bleeding and its
finishing property.
 Trial Mix 2: If the measured workability Trial mix 1
different from the stipulated value, the water and/or
admixture content shall be adjusted suitably. With thisadmixture content shall be adjusted suitably. With this
adjustment, the mix proportion shall be recalculated
keeping the free water-cement ratio at the pre-
selected value.
 Trial Mix 3: change water-cement ratio by + 10 % of
preselected or finally reached value and recalculate
mix proportions.

 Trial Mix 4: change water-cement ratio by - 10 % of
preselected or finally reached value and recalculate
mix proportions.
 Testing for trial mix numbers 2, 3, 4 are done
simultaneously.
 These tests normally provide sufficient information, These tests normally provide sufficient information,
including the relationship between compressive
strength and water-cement ratio, from which the
mix proportions for field trials may be arrived.

Trial mix No. 1 2 3 4
Final mix
proportions
Qty. per bag
of cement (kg)Ingredient Quantity per cu. meter
Water-cement ratio
Cement .
Water
C.A.-I ( %)
C.A.-II ( %)
F.A.
W
Mix Proportions Summary
W
O
R
K
ability
Slump(mm)
C.F.
Flow Table
Visual Observations
Comp.
Strength
(N/mm2)
7
Days
28
Days
Remark
17

Numerical problem on concrete mix design by is 10262(2009) method

Numerical problem on concrete mix design by is 10262(2009) method

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Numerical problem on concrete mix design by is 10262(2009) method