Project on Concrete Mix Design for various grades of Concrete
M35 GRADE CONCRETE WITH FLY ASH
Aim & Introduction:
The Aim of the mix design is to calculate and achieve the required compressive strength through mix
proportion for M35 grade concrete using fly ash.
Design Mix contains weigh batching and makes concrete of designed strength and also cost effective.
The design mix is the most intellectual and rational approach for selection of specific materials with
their proportions and more or less for their unique characteristics.
Procedure:
Data collection:
The grade of Concrete = M35
Exposure condition = Extreme (for reinforced concrete)
Grade of cement = OPC 43 (conforming to IS 8112)
fck = 35 N/mm^2.
Standard deviation for M35, S = 5.0
Maximum nominal size of aggregate = 20mm
Type of aggregate = Crushed angular aggregate
Degree of supervision = Good
Formulas:
Target mean strength : f’ck= fck +1.65 s
f’ck = target mean strength
fck= compressive strength at 28 days of concrete
s = standard deviation ( IS 10262:2009 , table -1)
Volume of cement : (mass of cement /specfic gravity of cement )x1 /1000
Volume of water : ( mass of water /specific gravity of water ) x1 /1000
Volume of chemical admixtures :( mass of chemical admixture / specific gravity of chemical
admixture)x 1/1000
Volume of fly ash : (mass of fly ash/specific gravity of fly ash )x 1/1000
Volume of concrete: 1 m^3
Volume of aggregates : ( volume of concrete -( volume of cement +volume of fly ash + volume of
water + volume of admixture )
Mass of coarse aggregates: volume of aggregate x volume of coarse aggregate x specific gravity of
coarse aggregate x1000
Mass of fine aggregate : volume of aggregate x volume of fine aggregate x specific gravity of fine
aggregate x1000
CODES FOR CONCRETE MIX DESIGN:
- IS 10262: 2009
- IS 456: 2000
- IS 8112
- IS 3812 ( part 1)
PROCEDURE AND CALCULATION:
- TARGET MEAN STRENGTH
F’ck = fck + 1.65 5
fck= 35 N/mm^2 (M35 )
Table 1- IS 10262:2009
s = 5 N/mm^2
f'ck = 35 + ( 1.65 x 5)
= 43.25 N/mm^2
2. SELECTION OF WATER CEMENT RATIO :
Given :
M35
Assume:
Exposure condition : Extreme ( for reinforced concrete)
Table 5 – IS 456 : 2000
Therefore,
Extreme= w/c ratio= 0.40
M35 = w/c ratio= 0.45
Lower the water cement ratio better the workability
0.40 < 0.45
Water cement ratio = 0.40
Minimum cement content = 360 Kg/m^3
3. SELECTION OF WATER CONTENT
Assume :
Nominal size of aggregates= 20 mm
Table 2 -IS 10262: 2009
Minimum water content = 186 litres or Kg
Slump ranges from 25 to 50 mm
As superplasticizers (20 % reduced)
= 186 x 80/100 = 148.8 (100-20 = 80)
Water content = 149 litres = 149 Kg
4. CALCULATION OF CEMETITIOUS CONTENT ( CEMENT + FLY ASH)
Water cement ratio = w/c= 0.40
Water content = W = 149 Kg
Cementitious content = c=149/0.40 = 372.5 = 370 Kg/m^3
Minimum cement content = 360 Kg/m^3
360< 370 Kg/m^3 ( hence okay )
Increase by 10 %
370 x 0.10 + 370 = 407 Kg/m^3
W= 149 Kg
Water cement ratio = 149/407 = 0.366
Fly ash at 30 % total cementitious material content
= 407 x 30/100 = 122 Kg/m^3
Cement (ordinary Portland cement ) = 407-122 = 285 Kg/m^3
Saving of cement while using fly ash = 370 – 285 = 85 Kg/ m^3
Fly ash = 122 Kg/m^3
5.VOLUME OF COARSE AGGREGATES AND FINE AGGREGATES
Fine aggregates are sieved according to zone 1 of table 4 IS 383
Coarse aggregates are sieved according to table 2 IS 383
According ,
Table 3 IS 10262: 2009
Nominal size of aggregates = 20 mm
Fine aggregates ( zone 1)
Therefore ,
Volume of coarse aggregate = 0.60
Water cement ratio = 0.4
( +/- 0.01 for every +/- 0.005)
So, volume of coarse aggregate = 0.62
Volume of fine aggregate = 1-0.62 = 0.38
6.MIX CALCULATION :
- Volume of concrete = 1m^3
- Volume of cement = (285 / 3.15) x1/1000 = 0.090 m^3
- Volume of fly ash = ( 122/2.2) x1/1000 =0.055 m^3
- Volume of water = ( 149/1)x 1/1000 =0.149 m^3
- Volume of admixture = ( 7.6/ 1.145)x1/1000 =0.006 m^3
- Volume of coarse aggregate and fine aggregate = a – ( b + c + d+
e) = 1-( 0.090 + 0.055 +0.149+ 0.006 ) = 0.7 m^3 - Mass of coarse aggregate = 0.7 x 0.62 x 2.74 x1000 = 1189.16 kg/m^3
- Mass of fine aggregate = 0.7 x 0.38 x 2.74 x1000 = 728 kg/m^3
RESULTS AND CONCLUSION :
TRIAL MIX:
Cement = 285 Kg/m^3
Fly ash = 122 Kg/m^3
Water = 149 Kg
Coarse aggregate = 1189 Kg/m^3
Fine aggregate = 728 Kg/m^3
Chemical admixture = 7.6 Kg/m^3
Water cement ratio = 0.366
Trial mix ratio : 285 :728 : 1189 = 1: 2.55 : 4.17 ( C: FA: CA)
- This trial mix ratio should match the workability ,durability, minimum strength of M35 grade concrete .
- If it does not satisfy the above criteria two or more trials for increase of 10 % should be done .
M50 GRADE CONCRETE
Aim & Introduction:
The Aim of the mix design is to calculate and achieve the required compressive strength through mix
proportion for M50 grade concrete using fly ash.
Design Mix contains weigh batching and makes concrete of designed strength and also cost effective.
The design mix is the most intellectual and rational approach for selection of specific materials with
their proportions and more or less for their unique characteristics.
Procedure:
Data collection:
The grade of Concrete = M50
Exposure condition = Severe (for reinforced concrete)
Grade of cement = OPC 43 (conforming to IS 8112)
fck = 50 N/mm^2.
Standard deviation for M35, S = 5.0
Maximum nominal size of aggregate = 20mm
Type of aggregate = Crushed angular aggregate
Degree of supervision = Good
Formulas:
- Target mean strength : f’ck= fck +1.65 s
f’ck = target mean strength
fck= compressive strength at 28 days of concrete
s = standard deviation ( IS 10262:2009 , table -1)
- Volume of cement : (mass of cement /specific gravity of cement )x1/1000
- Volume of water : ( mass of water/specific gravity of water ) x1 /1000
- Volume of chemical admixtures : ( mass of chemical admixture/ specific gravity of chemical admixture )x 1/1000
- Volume of concrete: 1 m^3
- Volume of aggregates : ( volume of concrete -( volume of cement + volume of water+volume of chemical admixture) )
- Mass of coarse aggregates: volume of aggregate x volume of coarse aggregate x specific gravity of coarse aggregate x1000
- Mass of fine aggregate : volume of aggregate x volume of fine aggregate x specific gravity of fine aggregate x1000
CODES FOR CONCRETE MIX DESIGN:
- IS 10262: 2009
- IS 456: 2000
- IS 8112
- IS 3812 ( part 1)
PROCEDURE AND CALCULATION:
- TARGET MEAN STRENGTH
F’ck = fck + 1.65 5
fck= 50 N/mm^2 (M50 )
Table 1- IS 10262:2009
s = 5 N/mm^2
f ‘ck = 50 + ( 1.65 x 5)
= 58.25 N/mm^2
2. SELECTION OF WATER CEMENT RATIO :
Given :
M50
Assume:
Exposure condition : Extreme ( for reinforced concrete)
Table 5 – IS 456 : 2000
Therefore,
Extreme= w/c ratio= 0.40
M50 = w/c ratio= 0.40
Lower the water cement ratio better the workability
0.40
Water cement ratio = 0.40
Minimum cement content = 360 Kg/m^3
3. SELECTION OF WATER CONTENT
Assume :
Nominal size of aggregates= 20 mm
Table 2 -IS 10262: 2009
Minimum water content = 186 litres or kg
Slump ranges from 25 to 50 mm
As superplasticizers (20 % reduced)
= 186 x 80/100 = 148.8 (100-20 = 80)
Water content = 149 litres
4.CALCULATION OF CEMENT CONTENT
Water cement ratio = w/c= 0.40
Water content = W = 149 Kg
Cement content = c=149/0.40 = 372.5 = 373 Kg/m^3
Minimum cement content = 360 Kg/m^3
360< 373 Kg/m^3 ( hence okay )
5.VOLUME OF COARSE AGGREGATES AND FINE AGGREGATES
Fine aggregates are sieved according to zone 1 of table 4 IS 383
Coarse aggregates are sieved according to table 2 IS 383
According ,
Table 3 IS 10262: 2009
Nominal size of aggregates = 20 mm
Fine aggregates ( zone 1)
Therefore ,
Volume of coarse aggregate = 0.60
Water cement ratio = 0.4
(+/- 0.01 for every +/- 0.005)
So, volume of coarse aggregate = 0.62
Volume of fine aggregate = 1-0.62 = 0.38
6.MIX CALCULATION :
- Volume of concrete = 1m^3
- Volume of cement = (373/3.15)x1/1000 = 0.118 m^3
- Volume of water = ( 149/1)x1/1000 = 0.149 m^3
- Volume of admixture = ( 7.6/1.145)x1/1000 = 0.006
- Volume of coarse aggregate and fine aggregate = a – ( b + c + d) = 1-( 0.118 + 0.149 + 0.006 )= 0.727 m^3
- Mass of coarse aggregate = 0.727 x 0.62 x 2.74 x1000 = 1235.02 kg/m^3
- Mass of fine aggregate = 0.727 x 0.38 x 2.74 x1000 = 756.9 kg/m^3
RESULTS AND CONCLUSION :
TRIAL MIX:
Cement = 373 Kg/m^3
Water = 149 Kg
Coarse aggregate = 1235.02 Kg/m^3
Fine aggregate = 756.9 Kg/m^3
Chemical admixture = 7.6 Kg/m^3
Water cement ratio = 0.40
Trial mix ratio : 373 :756.9 : 1235.02 = 1: 2.02: 3.31 ( C: FA: CA)
- This trial mix ratio should match the workability ,durability, minimum strength of M50 grade concrete .
- If it does not satisfy the above criteria two or more trials for increase of 10 % should be done .