Project on Concrete Mix Design for various grades of Concrete
Concrete Mix Design for M35 grade concrete with fly ash
specifications for the materials and requirements for the concrete to be manufacture
1) Grade of concrete =M35
2) Type of Cement = OPC 53 Confirming to IS8112
3) Type of Admixture = Fly ash
4) Maximum Nominal Size of Aggregate = 20mm
5) Using table 5 of IS 456 we get, Minimum Cement Content = 340kg
6) Maximum Cement Content = 450kg
7) Partial replacement of cement by Fly ash = 30%
8) Using table 5 of IS 456 we get, Maximum W/C ratio = 0.45
9) Workability = 100mm
10) Specific Gravity of Cement = 3.15
11) Specific Gravity of Fly ash = 2.9
12) As per IS 9103, Chemical Admixture = 0.6%
13) Specific Gravity of Coarse aggregate = 2.74
14) Specific Gravity of fine aggregate = 2.74
15) Specific Gravity of Admixture PCE based = 1.12
16) Water absorption of Coarse aggregate = 0.5%
17) Water absorption of fine aggregate = 1%
18) Sieve analysis of coarse aggregate is confirming to table 2 IS 383
19) Sieve analysis of fine aggregate is from zone-II confirming to table 4 IS 383.
TARGET STRENGTH, ft = fck + 1.65 x S
= 35+1.65 x5
= 43.25 N/mm2
SELECTION OF WATER-CEMENT RATIO : The maximum water-cement ratios for different grades of concrete are given in Table 5-IS456 and we can reduce the water-cement ratio based on our needs.
from table 5 IS 456 :
Maximum W/C ratio = 0.45
SELECTION OF WATER CONTENT FROM TABLE 2 IS 1026, Maximum Water Content = 186 Litres.
The water content above is for a slump of 25 to 50 mm, but according to the specification our concrete requires a slump of 100 mm. Therefore, to get the desired slump, the water content must be increased. Clause 4.2 of IS1026 recommends increasing the water content by 3% to obtain an additional 25 mm slump. Therefore, to obtain a slump of 50 mm in addition to our concrete, the water content must be increased by 6%.
Water-content for 100mm Slump = 186+(0.06x186) = 197.16 L
As we use super plasticizers we can reduce the water content to gain strength in the concrete. The amount of water-content to be reduced depends on the type of super plasticizer.
Percentage of Reduction in water content = 20%
Water content requirement after SP = 198 – (0.20x198) = 157.73 = 160 approx.
CEMENT AND FLY ASH CONTENT :
Adopted Water Cement Ratio = .45
Total Cementitious (Cement +Fly ash) requirement = Water Content / Water Cement ratio = 160/0.45 = 355.55 kg
Since flying ash is used, the amount of cementitious content (cement + fly ash) should be increased to get good performance and strength. The percentage of increasing cementitious content depends on experience and research. Here we have increased the cementitious content by 10%.
Final Cementitious Content (Cement+Fly ash) = 356x1.10 = 391.6 kg =
from table 5 IS 456, Minimum Cement Content required for ‘severe’ exposure = 340kg.
Hence OK.
Fly ash content requirement = 391.6 x 0.30 = 117.48 = 118 approx
Cement Content requirement = Cementious content – Fly ash = 391.6-117.48 = 274.12 kg
Calculation of Super Plasticiers at 0.6 percent to the mass of cementitious content = = 391.6x(0.6/100) = 2.35 kg
COARSE AND FINE AGGREGATE :
Coarse Aggregate ratio : 0.62 from table 3 IS 10262
Coarse Aggregate ratio for 0.45 w/c ratio = 0.63, adding 0.01 for every decrease 0.05
Maximum W/C ratio = 0.45
CALCULATIONS OF MIX DESIGN M35 GRADE CONCRETE,
A)Volume of Concrete = 1 Meter cube
B)Total Volume of Cement = 275/(3.15x1000) = 0.087 cu.m
C)Total Volume of Fly ash = 118/(2.5x1000) = 0.041 cu.m
D)Volume of Water = 160/(1x1000) = 0.160 cu.m
E)Volume of Superplasticizers = 2.35/(1.12x1000) = 0.002 cu.m
F)Total Aggregates requirement = A – (B+C+D+E) = 1 -(0.087 +0.041+0.160+0.002) = 0.71 cu.m
G)Coarse Aggregate (C.A) = F XC.A ratio X S.G X1000 = 0.71x0.63 x2.74 x1000 = 1225.6 kg
H) Fine Aggregate (F.A) = F x F.A ratio x S.G x 1000 = 0.71x0.37x2.74 x1000 = 719.8 kg
Mix Ratio of M35 Grade concrete by weight is Cement : Flyash: F.A : C.A : Water = 1:0.4:2.6:4.46:0.58
MIX DESIGN OF M50 CONCRETE WITHOUT FLY ASH :
Type of Concrete = RCC
1) Grade of concrete =M50
2) Type of Cement = OPC 53 Confirming to IS8112
3) Maximum Nominal Size of Aggregate = 20mm
4) Using table 5 of IS 456 we get, Minimum Cement Content = 340kg
5) Maximum Cement Content = 450kg
6) Using table 5 of IS 456 we get, Maximum W/C ratio = 0.45
7) Exposure Condition = severe
8) concrete placement = pumping
9) Slump = 50mm
10) Specific Gravity of Cement = 3.15
11) Specific Gravity of Fly ash = 2.9
12) chemical admixture volume by mass of cement 2% with water content reduction of 0%.
13) Specific Gravity of Coarse aggregate = 2.74
14) Specific Gravity of fine aggregate = 2.74
15) Specific Gravity of Admixture = 1.145
16) Water absorption of Coarse aggregate = 0.5%
17) Water absorption of fine aggregate = 1%
18) Sieve analysis of coarse aggregate is confirming to table 2 IS 383
19) Sieve analysis of fine aggregate is from zone-II confirming to table 4 IS 383.
20) Free Surface Moisture of Fine Aggregate = zero
21) Free Surface Moisture of coarse aggregate = zero
target mean compressive strength = characteristic strength + 1.65 X Standard Deviation = 50 + 1.65 X 5 = 58.25 N/mm2
Maximum water-cement ratio = 0.45.
Maximum water content for 20 mm aggregate and a slump value of 25 to 50 mm = 186.00 litres
The cement content per unit volume of concrete is computed sing Table 5 of IS:456:2000
Minimum cement content for severe expossure condition = 320 kg/ m3
cement content = 186/0.45 = 413.33 kg / m3
Volume of coarse aggregate per unit volume of total aggregate for corresponding to 20 mm maximum size and zone 1 of fine aggregate = 0.60 – Table 3 of IS- 10262:2009.
calculations
Coarse aggregate = 0.55
Fine aggregate = 0.45
from all the above data, we can calculate every quantity as calculated in previous M35 grade mix design. same formula can be used and we get
Mass of Coarse aggregate = 1027.08 kg / m3
Mass of Fine aggregate = 843.74 kg / m3
Coarse aggregate = 5.14 kg
Fine aggregate = 8.44 kg
MIX DESIGN
Cement = 413 kg / m3
Water = 200 kg / M3
Fine Aggregate = 835 kg / M3
Coarse Aggregate = 1022 kg / m3
FINAL MIX DESIGN : 1: 2.35: 2.86