Project on Concrete Mix Design for various grades of Concrete
CONCRETE MIX DESIGN FOR M35 GRADE CONCRETE WITH FLY ASH:
- Stipulations for proportioning:
a) Grade designation : M35
b) Type of cement : OPC 53 Grade conforming to IS 8112
c) Type of admixture : Fly ash
d) Max. nominal size of aggregate : 20mm
e) Min. cement content : 340kg/m^3 [From table IS 456]
f) Max.cement content : 450kg/m^3 [As per code]
g) Partial replacement of cement by Fly ash : 30% [As per requirement]
h) Max. water-cement ratio : 0.45 [From IS 456]
i) Workability : 100mm
j) Chemical admixture : PCS Type
2. Test data for materials:
a) Cement used : OPC 53 Grade conforming to IS 8112
b) Specific gravity of cement : 3.15
c) Mineral admixture : Fly ash [Confirming to IS12089]
d) Specific gravity of fly ash : 2.90
e) Chemical admixture : @0.6% [IS9103 ]
f) Specific gravity
- Coarse aggregate : 2.74
- Fine aggregate : 2.74
- Admixture PCE based : 1.12
g) Water absorption
- Coarse aggreagte : 0.5%
- Fine aggregate : 1.0%
h) Sieve analysis
- Coarse aggregate [Confirming to Table 2-IS383]
- Fine aggregate : Zone II [Confirming to Table 2-IS383]
3. Target strength for mix proportions:
Fck = fck + 1.65s ['S' from table I of IS10262]
= 35 + 1.65*5
Fck = 43.25 N/mm^2
4. Selection water-cement ratio:
From table 5 of IS456,
Max. water-cement ratio = 0.45
Based on experience, adapted water-cement ratio = 0.45
5. Selection of water content:
From table 2 of IS10262:2009,
Max. water content for 20mm aggregate = 186lts [for 25 to 50mm slump range]
Water content for 100mm slump = 186+6/100*186
= 197.16lts
As superplasticizers are used water content can be reduced upto 20%,
Water content requirement after SP = 198-(0.20*198)
= 157.73
Adopted water content = 160lts
6. Calculation of cement and fly ash content:
Water-cement ratio = 0.45
Total cementious (cement+fly ash) requirement = water content/water-cement ratio
= 160/0.45
= 355.55kg
Since Fly ash is used the amount of Cementitious content (Cement+Fly ash) shall be increased to get good workability and strength. Here we increased the cementitious content by 1.1 %.
Final cementious content (Cement+fly ash) = 356*1.1
= 391.6kg
Min. cement content required for severe exposure = 340kg [as per IS456 Table5]
Adapted cementious content = 391.6kg >340kg
Fly ash content requirement = 391.6*0.30 [30% replacement]
= 117.48 - 118kg
Cement content requirement = Cementious content-Fly ash
= 391.6-117.48
= 274.12
Calculation of Super Plasticiers @ 0.6 percent to the mass of cementitious content = = 391.6* (0.6/100) = 2.35 kg
7. Coarse and fine aggregate:
Coarse aggregate ratio = 0.62 [From IS10262 table 3 w/c 0.5]
Coarse aggregate ratio for 0.45 w/c ratio = 0.63
Final fine aggregate ratio = (1-0.63) = 0.37
8. Mix calculations for M35 grade:
a) Volume of concrete = 1m^3
b) Volume of cement = mass of cement/(S.G*1000)
= 275/(3.15*1000)
= 0.087 m^3
c) Volume of water = mass of water/(S.G*1000)
= 160/(1*1000)
= 0.160m^3
d) Volume of Fly ash = mass of fly ash/(S.G*1000)
= 118/(2.5*1000)
= 0.041m^3
e) Volume of superplasticizers = 2.35/(1.12*1000)
= 0.002m^3
f) Volume of aggregate = [a-(b+c+d+e)]
= [1-(0.087+0.04+0.160+0.002)]
= 0.71m^3
g) Mass of coarse aggregate = e*vol. of C.A*S.G*1000
= 0.71*0.63*2.74*1000
= 1225.6kg
h) Mass of fine aggregate = 0.71*0.37*2.74*1000
= 719.8kg
9. Mix proportions for M35 grade concrete:
Cement = 275kg
Fly ash = 118kg
Fine aggregate = 720kg
Coarse aggregate = 1226kg
Water =160L
PCE based super plasticizer = 2L
Therefore 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 FOR M50 GRADE CONCRETE WITHOUT FLY ASH:
- Stipulations for proportioning:
a) Grade designation : M50
b) Type of cement : OPC 53 Grade conforming to IS 8112
c) Max. nominal size of aggregate : 20mm
d) Min. cement content : 320kg/m^3 [From table IS 456 Exposure condition]
e) Max.cement content : 450kg/m^3 [As per code]
f) Max. water-cement ratio : 0.45 [From IS 456]
g) Exposure condition : Severe (For reinforced concrete)
i) Workability : 100mm
j) Chemical admixture : Super plasticizer
k) Method of concrete placing : Pumping
l) Degree of supervision : Good
m) Type of Aggregate : Crushed angular aggragates
2. Test data for materials:
a) Cement used : OPC 53 Grade conforming to IS1229-1989
b) Specific gravity of cement : 3.15
c) Chemical admixture : Super plasticizer conforming to IS1903
d) Specific gravity of CA : 2.74
e) Specific gravity of FA : 2.64
f) Water absorption of CA : 0.5%
g) Water absorption of FA : 1.0%
h) Free surface moisture of CA : Nil
i) Free surface moisture of FA : Nil
j) Sieve analysis: CA : Conforming to table 2 of IS383
k) Sieve analysis: FA : Conforming to grading zone II of table IS383
3. Target strength for mix proportioning:
f'ck=fck+1.65s
From table 1 of IS 10262:2009,
Standard deviation, s = 5 N/mm^2
f'ck = 50+1.65(5)
= 58.25 N/mm^2
4. Selection of water-cement ratio:
Maximum w/c ratio=0.45
It can be found from table 5 of IS456-2000 for severe exposure
Based on experience, adopted w/c ratio 0.44
0.44<0.45, hence ok
Adopted w/c ratio 0.44
5. Selection of water content:
From table 2 of IS 10262:2009 Max. water content for 20mm aggregate,
186litre (for 25 to 50mm slump range)
Increasing 3% of water content for every extra 25mm slump from 50mm slump so 6% is to added to it
186+(6/100)*186 = 197 litre
Estimated water content for 100mm slump,
if superplasticizer used 20% the water content is to be reduced up to and above
Based on trials with super plasticizer water content reduction of 20% has been achieved,
Hence the water content arrived
197*0.8 = 158lts
Water required = 158litres
6. Calculation of cement required:
Adopted w/c ratio = 0.44
Cement content = 158/0.44 = 359kg/m^3
From table 5 of IS 456, Min. cement content for Severe exposure conditions,
320>359kg/m^3 Hence ok
Cement required 359kg/m^3
7. Volume of coarse and fine aggregate content:
From table 3 of IS 10262:2009 volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate (zone II) for w/c ratio is 0.50 0.62
In the present case w/c ratio is 0.44. Therefore volume of coarse aggregate is to be increased to decreased on fine aggregate content. As the w/c ratio is lower by 0.06. The proportion of volume of coarse aggregate is increased by 0.02
Therefore corrected portion of volume of coarse aggregate for w/c ratio is 0.44 0.632
For pumpable concrete these values should be reduced upto 10%. Therefore volume of coarse aggregate
0.632x0.9 = 0.568
Volume of fine aggregate 1-0.576 = 0.431
Volume of fine aggregate and coarse aggregate is 0.431 and 0.568
8. Mix calculations:
a) Volume of concrete = 1m^3
b) Volume of cement = mass of cement/(S.G*1000)
= 359/(3.15*1000)
= 0. m^3
c) Volume of water = mass of water/(S.G*1000)
= 158/(1*1000)
= 0.158m^3
e) Volume of Chemical admixture = 7.6/(1.145*1000)
= 0.006m^3
f) Volume of aggregate = [a-(b+c+d+e)]
= [1-(0.114+0.158+0.006)]
= 0.722m^3
g) Mass of coarse aggregate = e*vol. of C.A*S.G*1000
= 0.722*0.56*2.74*1000
= 1123kg
h) Mass of fine aggregate = 0.722*0.431*2.74*1000
= 821kg
9. Mix proportions for M50 grade concrete:
Cement = 359kg
Fine aggregate = 821kg
Coarse aggregate = 1123kg
Water =158l
W/c ratio = 0.44
Chemical admixture = 7.18
Mix Proportion by weight = 1:2.28:3.12