CONCRETE DESIGN MIX

1. SECTION-VIII
CONCRETE TECHNOLOGY
CE-304
NATIONAL INSTITUTE OF TECHNOLOGY, JOTE, ARUNACHAL
PRADESH, 791112
An Institute of National Importance under Ministry of Education
(Shiksha Mantralaya), Government of India

2. SECTION-VIII- DESIGN MIX AS PER IS 10262-2019
 As per IS 10262-2019, determine the concrete mix proportioning of M40 Grade concrete. Given data: -
 Grade designation: M40
 Type of cement:- OPC 43 Grade
 Type of cement: PPC conforming to IS 1489 (Part 1)
 Maximum nominal size of aggregate: 20 mm
 Minimum cement content and maximum water-cement ratio to be adopted and/or: Severe (for reinforced concrete) Exposure
conditions as per Table 3 and Table 5 of IS 456
 Workability: 120 mm (slump)
 Method of concrete placing: Pumping
 Degree of site control: Good
 Type of aggregate: Crushed angular aggregate
 Maximum cement content : 450 kg/m3
 Chemical admixture type: Superplasticizer – normal
 Mineral Admixture: - Fly Ash
TEST DATA FOR MATERIALS
 Cement used: OPC 43 Grade
 Specific gravity of Fly ash:- 2.2
 Specific gravity of cement: 3.15
 Chemical admixture: Superplasticizer conforming to IS 9103
 Specific gravity of Coarse aggregate: 2.74
 Fine aggregate: 2.65
 Chemical admixture: 1.145

3. SECTION-VIII- DESIGN MIX AS PER IS 10262-2019 CONTINUE…
 Before continuing the numerical let us discuss few points from IS Code so that we can take data directly.
 The below graph will help to find the W/C ratio

4. SECTION-VIII- DESIGN MIX AS PER IS 10262-2019 CONTINUE…
 The below table will help to use the standard deviation

5. SECTION-VIII- DESIGN MIX AS PER IS 10262-2019 CONTINUE…
 The below table will help to use the amount of water:- only for 50 mm slump
 Mineral Admixtures:- (Metakaoline is used in the production of ceramics and the is less than 1 to 2 micro meter.
(China clay is example of metakoline)

6. SECTION-VIII- DESIGN MIX AS PER IS 10262-2019 CONTINUE…
 The below table will help to compare the Max. W/C Ratio :-

7. SECTION-VIII- DESIGN MIX AS PER IS 10262-2019 CONTINUE…
 Solution:
 Target Mean Strength:-
 On putting all the values in above formula we get:-
f’ck = 40 + 1.65 x 5.0
f’ck = 48.25 N/mm2
 On the basis of above target mean strength, we can have the value of W/C ratio from slide no. 3
 We obtained the W/C = 0.36
 Now from slide No. 6 as per severe condition we have the Max. W/C Ratio of 0.45. And as per our calculation we have W/C ratio
of 0.36. Means 0.36 < 0.45 (Hence Ok)
 BEFORE CONTINUING FEW POINTS TO REMEMBER AS PER IS 10262-2019:-
 High strength concrete is the concrete that has characteristic compressive strength of 65 N/mm2 or more.
 High strength concrete mixes usually have a low water cementitious materials ratio (w/cm). These low w/cm ratios are generally
only attainable with high-range water-reducing admixtures (HRWRA). PCE type (Poly carboxylate ether based) super
plasticizers which reduce water content by 30 percent or above.
 For ordinary concrete and standard concrete we can reduce water content 5 to 10 percent and 20 to 30 percent.

8. SECTION-VIII- DESIGN MIX AS PER IS 10262-2019 CONTINUE…
 Selection of water content:
 From slide 5 we can see the amount if water required for maximum size of aggregate is= 186 kg (For 50 mm slump)
 As per IS 10262-2019, Clause No. 6.2.4, For the desired workability (other than 50 mm slump), the required water content may be
increased or decreased by about 3 percent for each increase or decrease of 25 mm slump.
 Estimated water content for 120 mm slump (increasing at the rate of 3 percent for every 25 mm slump)
Therefore, Estimated water content for 120 mm slump = 186 + (8.4/100) x 186 = 201.62 kg
 As superplasticizer is used, the water content may be reduced. Based on trial data, the water content reduction of 23 percent is
considered while using superplasticizer at the rate 1.0 percent by weight of cement.
Hence the arrived water content = 201.62 - (23/100) x 201.62
155.25 kg ≈ 155 kg.
 Now we have to calculate amount of cement content:-
 Water-cement ratio (W/C) = 0.36
 Cement content = 155/0.36 = 430.55 kg/m3 ≈ 431 kg/m3
 From slide no.6 we can see for severe condition minimum cement content is= 320 kg/m3 which is smaller than 431 kg/m3 (Hence
the condition is ok) and also as per given criteria the maximum cement content is 450 kg/m3 which is greater than 431 kg/m3
(Hence condition is ok).
 Fly ash @ 30 percent of total cementitious material content (As given in slide no.5)
 Total amount of fly ash :- (30/100) x 431 = 129.3 kg/m3
 Total mass of OPC Cement:- 431 – 129.3 = 301.7 kg/m3

9. SECTION-VIII- DESIGN MIX AS PER IS 10262-2019 CONTINUE…
 PROPORTION OF VOLUME OF COARSE AGGREGATE AND FINE AGGRAGETE CONTENT:

10. SECTION-VIII- DESIGN MIX AS PER IS 10262-2019 CONTINUE…
 PROPORTION OF VOLUME OF COARSE AGGREGATE AND FINE AGGRAGETE CONTENT:
 From slide no. 9 volume of coarse aggregate corresponding to 20 mm size aggregate and fine aggregate (Zone II) for water-cement ratio of 0.50 =
0.62. (Depends on you which zone you are preferring, except zone-IV)
 In the present case water-cementitious ratio is 0.36.
 Note:- The proportion of volume of coarse aggregates to that of total aggregates is increased at the rate of 0.01 for every decrease in water-
cement/cementitious materials ratio by 0.05 and decreased at the rate of 0.01 for every increase in water cement ratio by 0.05.
 The difference in the W/C ratio of the volume of coarse aggregate to the actual is= 0.50-0.36 = 0.14 (Here we have decrease in the W/C ratio).
 The proportion of volume of coarse, aggregate is increased by 0.028 (at the rate of ∓ 0.01 for every ± 0.05 change in water cement ratio). Therefore,
corrected proportion of volume of coarse aggregate for the water-cement ratio of 0.36 = 0.62 + 0.028 = 0.648.
 (0.14/0.05) X 0.01 = 0.028 (Rough work)
 For pumpable concrete these values may be reduced by up to 10 percent
 Volume of Coarse Aggregate = 0.648 – 0.0648 = 0.5832 ≈ 0.59 m3
 Volume of fine aggregate content = 1 – 0.59 = 0.41 m3
 MIX CALCULATIONS:-
a) Total volume of concrete= 1 m3
b) Volume of entrapped air in wet concrete =0.01 m3
c) Volume of cement = (Mass of cement/ Specific Gravity of cement) x (1 /1000)
d) Volume of water = (Mass of Water/ Specific Gravity of Water) x (1 /1000)
e) Volume of Fly Ash= (Mass of Fly Ash/ Specific Gravity of Fly Ash) x (1 /1000)
f) Volume of chemical admixture (superplasticizer) (@ 1.0 percent by mass of cementitious material)= (Mass of Chemical Admixture/ Specific
Gravity of Chemical Admixture) x (1 /1000)
g) Volume of all in aggregate = [(a-b)-(c+d+e+f)]
h) Mass of coarse aggregate = g) × Volume of coarse aggregate × Specific gravity of coarse aggregate × 1000
i) Mass of fine aggregate = g) × volume of fine aggregate × Specific gravity of fine aggregate × 1000

11. SECTION-VIII- DESIGN MIX AS PER IS 10262-2019 CONTINUE…
 MIX PROPORTIONS FOR TRIAL NUMBER:-
CEMENT
FLY ASH
WATER
FINE AGGREGATE
COARSE AGGREGATE
CHEMICAL ADMIXTURE
W/C RATIO