Project on Concrete Mix Design for various grades of Concrete
Aim - To find out the mix proportion for M35 grade of concrete with fly ash .
Introduction - i) Generlly Fly ash is added in a concrete to reduced the amount of portland cement.
ii) It improves the workability and durability of concrete .
iii) It is an cost effective material , so overall cost of the concrete can be reduced .
Assume the Stipulations For Proportioning of M35 grade concrete As per IS 10262 : 2009
| Sr No | Properties | Values / type |
| 1 | Grade Designation | M35 |
| 2 | Type of cement | OPC 43 grade confining to IS 8112 |
| 3 | Type of mineral admixture | Fly ash confining to IS 3812 |
| 4 | Max size of aggregate | 20 mm |
| 5 | Minimum Cement content | 340 kg/m3 ( Is 456:2000) Exposure condition |
| 6 | Exposure condition | Very Severe ( for RCC) |
| 7 | Maximum water cement ratio | 0.45 ( Severe condition) from IS 456:2000 |
| 8 | Workability | 100 mm (slump for pumable concrete ) |
| 9 | Partila replacement of cement by fly ash | 30% as per requiremets |
Procedure - Following data are collected by performing standard test in laboratory -
i) Sp.gravity of cement - 3.15
ii) Fly ash -( Is 3812) part 1
iii) Sp.gravity of Fly ash - 2.2
iv) Sp.gravity of coarse aggregate - 2.74
v) Sp.gravity of fine aggregate - 2.74
vi) water absorption for CA - 0.5 %
vii) water absorption for FA - 1%
viii) Sieve Analysis - Fine aggregate Confining Zone 1
Step 1) Target strength of mix proportion -
ft = fck + 1.65 x S
where , ft = target mean strength
fck = characterstics compressive strength after 28 days in N/mm2
S = Standard deviation
( For M35 grade of concrete , S = 5 N/mm2 - As per Is 10262 :2009)
therefore ,
ft = fck + 1.65 x S
= 35 + 1.65 x 5
= 43.25 N/mm2
Step 2) Selection of water cement ratio -
Water cement ratio can be calculated by three methods
i) Calculate water cement ratio by Graph 1 ( Is 10262 : 2009)
ii) Calculate water cement ratio by Graph 2 ( IS 10262 : 2009
iii) Calculate water cement ratio by Enviromental condition -( IS 456:2000)
So , We calculate Water cement ratio by Enviromental condition -
Enviromental condition - Very Severe
Therefore ,
Water cement ratio as per (IS 456: 2000) = 0.45
But as per practical experienced assume water cement ratio = 0.4
Hence , 0.4 < 0.45..........................Ok
Step 3) Selection of water content -
As per IS 10262: 2009 the maximum water content for 20 mm nominal size aggregate is 186 lit
( for 25 mm to 50 mm slump value )
We have assume 100 mm slump , So for every increse in 25 mm slump the water content
is increased by 3%
Therefor ,
For 100 mm slump = 186 + 6%
= 197 lit
Now , we are using Superplasticizer , which reduces water content by 30%
but based on trials water content is reduced by 29%
Therefore ,
Water Content = 197 x 0.71
= 140 lit
Step 4) Calculation of Cementatious ( Cement + Fly Ash)
Cementatious content = Water content
(Cement + Fly ash) __________________
Water Cement ratio
= 140
_____
0.4
= 350 kg / m3
So , Minimum Cement content for exposure condition As per IS 456 : 2000 is 340Kg /m3
Therefore ,
350 kg/m3 > 340 kg/m3.........................................Ok
Step 5) Proportion of mix containing Fly ash -
To find the proportion of fly ash following steps are followed -
i) The percenatage of fly ash is decided on project requirement and quality of materials .
ii) In some cases increases in cementatious materials can be warrned .
So in this case we increases cementatious materials by 10%
Therefore ,
Cementatious materials = 350 x 1.10
= 385 kg/m3
Water content = 140lit
Water cement ratio = 140
________
385
= 0.364
Fly Ash @ 30% of total = 385 x 30%
cementatious materials = 115 kg / m3
Therefore ,
Cement = 385 - 115
= 270 kg/m3
So , We have save cement = 350 - 270
= 80kg /m3
We have save 80 kg/m3 cement by using Fly Ash .
Step 6) Volume of coarse aggregate and fine aggregate -
AS per IS 10262: 2009 for 20 mm nominal size of aggregate , the volume of coarse aggregate is
0.60 ( Zone 1) for maximum water cement ratio .
But in our case w/c ratio is 0.40 ,
So ,
As per IS 10260: 2009 if w/c ratio decreases then volume of coarse agggregate needs to
be increased at the rate of 0.01 for every change of 0.05 w/c ratio
Hence for 0.40 w/c ratio Volume of CA = 0.64
But for Pumable concrete value should be reduced by 10%
Vol of CA = 0.64 x 0.9
= 0.576
Vol of FA = 1-0.576
= 0.424
Step 7) Mix Calculation - For per unit volume of concrete
i) Volume of concrete = 1m3
ii) Volume of cement = (Mass of cement / Sp gravity of cement ) x 1/1000
= (270 / 3.15) x 1/1000
= 0.086 m3
iii) Volume of Fly Ash = (Mass of Fly Ash / Sp gravity of Fly Ash ) x 1/1000
= (115/2.2) x 1/1000
= 0.052 m3
iv) Volume of water = (Mass of water / Sp gravity of water ) x 1/1000
= (140/1 ) x 1/1000
= 0.140 m3
iv) Vol of admixture = ( Mass of admixture / sp gravity of admixture) x 1/1000
= 7/1.145 x 1/1000
= 0.006 m3
v) Vol of all in aggregate = 1 - ( 0.086+0.052 + 0.140+ 0.006)
= 0.716 m3
vi) Mass of CA = Vol of aggregate x Vol of CA aggreagte x sp gravity of CA x 1/1000
= 0.716 x 0.576 x 2.74 x 1/1000
= 1130 kg
vii) Mass of FA = Vol of aggregate x Vol of FA aggreagte x sp gravity of FA x 1/1000
= 0.716 x 0.424 x 2.74 x 1/1000
= 831 kg
Step 8) Mix Proportion -
| 1 | Cement | 270 kg/m3 |
| 2 | Fly Ash | 115 kg/m3 |
| 3 | Fine aggregate | 831 kg/m3 |
| 4 | Coarse aggregate | 1130 kg/m3 |
| 5 | Water | 140 kg/m3 |
| 6 | Chemical Admixture | 7 kg/m3 |
| 7 | Water Cement Ratio | 0.364 |
| 8 | Mix Ratio | 1:2.15:2.94 |
Step 9) Note -
i) Two more trials needs to be taken which is having variation of 10% of water cement ratio.
ii) Water cement ratio carried out by three methods corresponding to compressive strength and
graph is plotted to obtain the water cement ratio .
RESULT -
The Mix Design for M35 grade of concrete with fly ash is 1:2.15:2.94
Design of M50 grade concrete without fly ash
Aim - To find out the mix proportion for M50 grade of concrete without fly ash .
Introduction -
Assume the Stipulations For Proportioning of M35 grade concrete As per IS 10262 : 2009
| Sr No | Properties | Values / type |
| 1 | Grade Designation | M50 |
| 2 | Type of cement | OPC 43 grade confining to IS 8112 |
| 3 | Max size of aggregate | 20 mm |
| 4 | Minimum Cement content | 320 kg/m3 ( Is 456:2000) Exposure condition |
| 5 | Exposure condition | Severe ( for RCC) |
| 6 | Maximum water cement ratio | 0.45 ( Severe condition) from IS 456:2000 |
| 7 | Workability | 100 mm (slump for pumable concrete ) |
| 8 | Chemical Admixture | Superplasticizer |
Procedure - Following data are collected by performing standard test in laboratory -
i) Sp.gravity of cement - 3.15
ii) Sp.gravity of coarse aggregate - 2.74
iii) Sp.gravity of fine aggregate - 2.74
iv) water absorption for CA - 0.5 %
v) water absorption for FA - 1%
vi) Sieve Analysis - Fine aggregate Confining Zone 1
vii) Chemical Admixture - Superplasticizer (IS9103)
Step 1) Target strength of mix proportion -
ft = fck + 1.65 x S
where , ft = target mean strength
fck = characterstics compressive strength after 28 days in N/mm2
S = Standard deviation
( For M35 grade of concrete , S = 5 N/mm2 - As per Is 10262 :2009)
therefore ,
ft = fck + 1.65 x S
= 50 + 1.65 x 5
= 58.25.25 N/mm2
Step 2) Selection of water cement ratio -
Water cement ratio can be calculated by three methods
i) Calculate water cement ratio by Graph 1 ( Is 10262 : 2009)
ii) Calculate water cement ratio by Graph 2 ( IS 10262 : 2009
iii) Calculate water cement ratio by Enviromental condition -( IS 456:2000)
So , We calculate Water cement ratio by Enviromental condition -
Enviromental condition - Severe
Therefore ,
Water cement ratio as per (IS 456: 2000) = 0.45
But as per practical experienced assume water cement ratio = 0.4
Hence , 0.4 < 0.45..........................Ok
Step 3) Selection of water content -
As per IS 10262: 2009 the maximum water content for 20 mm nominal size aggregate is 186 lit
( for 25 mm to 50 mm slump value )
We have assume 100 mm slump , So for every increse in 25 mm slump the water content
is increased by 3%
Therefore ,
For 100 mm slump = 186 + 6%
= 197 lit
Now , we are using Superplasticizer , which reduces water content by 30%
but based on trials water content is reduced by 29%
Therefore ,
Water Content = 197 x 0.71
= 140 lit
Step 4) Calculation of Cement Content
Cement content = Water content ___________________
Water Cement ratio
= 140 ___
0.4
= 350 kg / m3
So , Minimum Cement content for exposure condition As per IS 456 : 2000 is 320Kg /m3
Therefore ,
350 kg/m3 > 320 kg/m3.........................................Ok
Step 5) Volume of coarse aggregate and fine aggregate -
AS per IS 10262: 2009 for 20 mm nominal size of aggregate , the volume of coarse aggregate is
0.60 ( Zone 1) for maximum water cement ratio .
But in our case w/c ratio is 0.40 ,
So ,
As per IS 10260: 2009 if w/c ratio decreases then volume of coarse agggregate needs to
be increased at the rate of 0.01 for every change of 0.05 w/c ratio
Hence for 0.40 w/c ratio Volume of CA = 0.64
But for Pumable concrete value should be reduced by 10%
Vol of CA = 0.64 x 0.9
= 0.576
Vol of FA = 1-0.576
= 0.424
Step 6) Mix Calculation - For per unit volume of concrete
i) Volume of concrete = 1m3
ii) Volume of cement = (Mass of cement / Sp gravity of cement ) x 1/1000
= (350 / 3.15) x 1/1000
= 0.111 m3
iii) Volume of water = (Mass of water / Sp gravity of water ) x 1/1000
= (140/1 ) x 1/1000
= 0.140 m3
iv) Vol of admixture = ( Mass of admixture / sp gravity of admixture) x 1/1000
= 7/1.145 x 1/1000
= 0.006 m3
v) Vol of all in aggregate = 1 - ( 0.111 + 0.140+ 0.006)
= 0.743 m3
vi) Mass of CA = Vol of aggregate x Vol of CA aggreagte x sp gravity of CA x 1/1000
= 0.743 x 0.576 x 2.74 x 1/1000
= 1173 kg
vii) Mass of FA = Vol of aggregate x Vol of FA aggreagte x sp gravity of FA x 1/1000
= 0.743 x 0.424 x 2.74 x 1/1000
= 863 kg
Step 8) Mix Proportion -
| 1 | Cement | 350 kg/m3 |
| 2 | Fine aggregate | 863 kg/m3 |
| 3 | Coarse aggregate | 1173 kg/m3 |
| 4 | Water | 140 kg/m3 |
| 5 | Chemical Admixture | 7 kg/m3 |
| 6 | Water Cement Ratio | 0.4 |
| 7 | Mix Ratio | 1:2.46:3.35 |
Step 9) Note -
i) Two more trials needs to be taken which is having variation of 10% of water cement ratio.
ii) Water cement ratio carried out by three methods corresponding to compressive strength and
graph is plotted to obtain the water cement ratio .
RESULT -
The Mix Design for M35 grade of concrete with fly ash is 1:2.46:3.35