Trail No 198 – M50 BHARATHI + CHRYSO
CONCRETE MIX PROPORTIONING DETAILS
A. STIPULATIONS FOR PROPORTIONING
a) Grade Designation : M50
b) Type of Cement : OPC 53 grade conforming to IS 12269
c) Type of mineral admixture : GGBS conforming to 12089-1987
d) Maximum nominal size of aggregate : 20mm
e) Minimum cement content for 20mm : 380 kg/m3 ( As per MORTH Table 1700-2)
f) Maximum water cement ratio : 0.40 ( As per MORTH Table 1700-2)
g) Workability : 100mm to 150mm ( Slump)
h) Exposure condition : Very Severe ( for Reinforced concrete)
i) Method of concrete placing : Direct by chute
j) Degree of supervision : Good
k) Type of aggregate : Crushed angular aggregate
l) Maximum cement (OPC) content : 450 kg/m3
m) Chemical Admixture type : PCE based
B. TEST DATA FOR MATERIALS
a) Cement Used : OPC 53 grade conforming to IS 12269
b) Specific gravity of Cement : 3.10
c) GGBS : Conforming to IS 12089 (1987)
d) Specific gravity of GGBS : 2.88
e) Chemical Admixture : High Water Reducing - conforming to IS 9103
f) Specific Gravity of:
1. Coarse Aggregate 20mm : 3.05
2. Coarse Aggregate 10mm : 3.01
3. Crushed Rock Fine ( CRF) : 2.80
g) Water Absorption :
1. Coarse Aggregate 20mm : 0.62
2. Coarse Aggregate 10mm : 0.66
3. Crushed Rock Fine ( CRF) : 1.41
h) Source of material :
1. Cement = BHARATHI OPC 53
2. GGBS = PISSURLEM
3. Coarse Aggregate = BELGAUM
4. Crushed Rock Fines = RAMANAGAR
5. Water = BAINA
6. Admixture = CHRYSO
C. TARGET STRENGTH FOR MIX PROPORTIONING
f’ck = fck + current margin
where f’ck = Target average compressive strength at 28 days,
fck = characteristic compressive strength at 28 days,
As per IRC 21-2000 Table 6 for M50 Grade current margin is: 13 N/mm2
Therefore, target strength = 50 + 13 = 63 N/mm2
D. SELECTION OF WATER CEMENT RATIO
From Table 1700-2 of MoRTH Maximum water binder ratio = 0.40
Based on experience, adopt water-cement ratio as 0.28
0.28 < 0.40, Hence OK
E. SELECTION OF WATER CONTENT
From Table 2, maximum water content for 20mm aggregate = 186 litre (for 25 to 50mm slump
range)
Estimated water content for 100-150 mm slump = 186 + 12/100 x 186 = 209 litre
As Superplasticizer is used, the water content can be reduced up to 23.5 percent.
Based on trails with Superplasticizer water content reduction of 76.5 percent has been achieved.
Hence, the arrived water content = 209 x 0.765 = 160 litres.
F. CALCULATION OF CEMENT AND GGBS CONTENT
Water- cement ratio = 0.28
Cementitious material (Cement + GGBS) content = 160/0.28 = 571 kg/m3 say 572 kg/m3
As per MORTH Table 1700-2, minimum cement content for ‘Very Severe’ exposure conditions
= 380kg/m3
572 kg/m3 > 380kg/m3, Hence O.K.
GGBS @ 50% of total cementitious material content = 572 x 50% = 286 kg/m3
Cement (OPC) = 572 – 286 = 286 kg/m3
G. BLENDING AND PROPORTIONING OF AGGREGATE
COMBINED GRADING GRAPH
Limits
Seive Individual Combined for
Size Grading Grading concrete
mix
(mm) 40mm 20mm 10mm CRF Nsand U. Limit L. Limit
0% 28.50 % 28.50 % 43.00 % 0%
40 100.00 100.0 100.0 100.0 100 100
20 98.22 100.0 100.0 99.49 95 100
10 9.66 95.54 100.0 72.98
4.75 0.90 14.33 98.95 46.89 30 50
2.36 0.0 1.50 80.92 35.22
1.18 59.64 25.65
0.6 50.19 21.58 10 35
0.3 21.37 9.19
8.01 3.44
0.15 0 6
H. MIX CALCULATIONS
The mix calculations per unit volume of concrete shall be as follows:
a) Volume of concrete = 1 m3
b) Volume of cement = (Mass of cement / Specific gravity of cement) x (1/1000)
= (286 / 3.10 ) x (1/1000)
= 0.0922 m3
c) Volume of GGBS = ( Mass of GGBS/ Specific gravity of GGBS) x (1 / 1000)
= (286 / 2.88) x (1/1000)
= 0.099 m3
d) Volume of water = (Mass of water/ Specific gravity of water) x (1/1000)
= (160/1) x (1/1000)
= 0.160m3
e) Volume of Admix = (Mass of admix/ Specific gravity of Admix) x (1/1000)
= (4.00/1.03) x (1/1000)
= 0.0039 m3
f) Volume of all in aggregate = [ a – (b + c + d )]
= 1 – (0.0922 + 0.099 + 0.160 + 0.0039)
= 0.6449 m3
g) Mass of Coarse aggregate & Fine Aggregate :
i. Quantity of 20mm C.A.= 0.645 x 0.285 x 3.05 x 1000
= 560.00 Kg
ii. Quantity of 10mm C.A.= 0.645 x 0.285 x 3.01 x 1000
= 553.00 Kg
iii. Quantity of CRF .= 0.645 x 0.43 x 2.80 x 1000
= 776.00 Kg
Note: Aggregate proportion can be changed as per site condition & Admixture dosage can
be varied as per Climatic condition.
I. FINAL PROPORTIONING OF CONCRETING:
SL.NO. MATERIAL INGREDIENTS
01 Cement 286 Kg
02 GGBS 286 Kg
03 20mm C.A. 560 Kg
04 10mm C.A. 553 Kg
05 CRF 776 Kg
06 Water 160 Kg ( W/B 0.28)
07 Admixture 4.00 Kg (0.70 %)
