Project on Concrete Mix Design for various grades of Concrete
: MIX DESIGN FOR M35 GRADE CONCRETE WITH FLY-ASH :
AIM :- Mix design for M35 grade concrete with fly ash.
INTRODUCTION OF CONCRETE MIX DESIGN:-Conrete mix design is a systematic process of choosing economical realative proportions of various ingredients from available material thar gives the concrete of desired workability. The process selecting suitable ingredients for producting concrete of required strenght durability , and workability as economical as possible is known as concrete Mix design.
Procedure:
Step:1
Stipulation For Proportioning:-
- Grade Designation : M35
- Type of Cement: OPC 43 grade (as IS-8112)
- Type of minereal admixture: Fly ash (From IS-3812 Part-1)
- Maximum nominal size of aggregate: 20mm
- Minimum Cement conctent : 320 `kg/m^3`(From Table-5 of IS-456:2000, based on Exposure Condition)
- Maximum water cement ratio: 0.45 (From table-5 of IS-456:2000 , based on Exposure Condition)
- Workabillity: 100 mm slump value of pumpable concrete
- Exposure condition: Severe (For Reinforced Concrete)
- Method Of Concrete Placing: Pumping
- Degree Of Supervision: Good
- Type Of aggregate: Crushed Angular aggregate
- Maximum Cement Content: 450`kg/m^3`.
- Chemical Admixture: Superplasticizer
Step:2
Test Data For Materials:
- Cement used: OPC 43 grade (Confirming to IS-8112)
- Specific Gravity of Cement : 3.15
- Flyash :
Specific gravity of flyash : 2.2
chemical admixture: Superplasticizer (Confirming to IS-9103) - Specific Gravity of:
- Fine Aggregate: 2.74
- Course Aggregate :2.74 - Water Absorption:
- FineAggregate: 1.0
- Coarse Aggregate : 0.5 - Free Surface Moisture:
- Fine Aggregate: Nill
- Coarse Aggregate:Nill - Sieve Analysis:
Coarse Aggregate
Fine Aggregate (confirmig to grading Zone-1 of Table-4 of IS-383)
Step:3
To find Target Mean Strenght for mix proportioning:
Target mean Strenght f'ck = fck + 1.65*s
= 35+1.65*5
= 43.25 `N/mm^2`
Where,
fck-Charasteristics Compressive strenght
f'ck-Target Average Compressive Strenght at 28 days
S- Standard Deviation
From table-1 of IS-10262:2009, Standard Deviation S= 5`N/mm^2`
Step:4
Selection of Water cement ratio:
Maximum Water-Cement Ratio = 0.45
On Experience water Cement ratio = 0.4
0.4<0.45, hence OK.
Step:5
Calculation of Water Content:
Maximum Water content for 20mm aggregate = 186 litres(From table-2 of IS-10262:2009) for 25 mm to 50 mm slump range
for 100mm slump = 186 +(6/100)*186 = 197 litres
As superplasticizer is used the water content is reduced upto 30%
Based on trials water content reduction of 29% is achieved with plasticizer.
Hence arrived water content = 197*0.71= 140
Step:6
Calculation of Cement content:
Water-Cement Ratio- 0.4
Cementatious material (Cement +flyash)= 140/0.4= 350`kg/m^3`
in table-5 of IS-456:2000, the cement content for sever Exposure = 320 `kg/m^3`
350`kg/m^3`> 320`kg/m^3`
Hence OK.
To propotion the Mix containing flyash the folowing steps are suggested:
- The percentage of the flyash need to be decided based on project requirement and quality of materials.
- In some cases increase in cementatious matrial can be warrend . increase in cementatious material content and its prcentage may be based on experience and trial
in this increase of 10% cementatious material content is considered.
comentatious material = 350*1.1= 385 `kg/m^3`
Water content =140`kg/m^3`
So, Water-cement ratio = 140/ 385 = 0.364
Fly ash at 30% total Cementatious material content = 35-30% =115 `kg/m^3`
Cement (OPC) = 385 -115 = 270 `kg/m^3`
Savings of cement while using flyash = 350- 270= 80`kg/m^3`
Flyash beign utilized = 115 `kg/m^3`
Step:7
Proportion of coarse aggregate and fine aggregate content:
From table-3 of IS-10262:2009 , volume of coarse aggregate correspondig to 20mm size aggregate and fine aggregate (Zone-1) for water cement ratio . = 0.6
in Present case the water- cement ratio is 0.4
Therefore the volume of coarse aggregate needs to be increased to decrease the fine aggregate content.
As the water- cement ratio is lowered by 0.1 , the proportion of volume of coarse aggregate is increase by 0.02 (at the rate of +/-0.01 for every +/- 0.05 change in water cement ratio )
Hence the Corrected value of Coarse aggregate for water -cement ratio = 0.64
(If Coarse aggregate is not angular type , then also the volume of coarse aggregate may be required to be increased suitably , based on experience)
For pumpable concrete , these are reduced by 10%
volume of coarse aggregate = 0.64*0.9=0.576
volume of fine aggregate = 1-0.576= 0.424
Step:8
MIX CALCULATION
- Volume of concrete - 1m^3
- Volume of cement = Volume of Cement = (Mass of cement/Specific gravity of cement) *(1/1000)
= (270/3.15)*(1/1000)
= 0.086`m^3`
c. Volume of Fly Ash= (mass of flyash/Specific gravity of flyash)*(1/1000)
= (115/2.2)*(1/1000)
=0.052 `m^3`
d. Volume of water = (Mass/Specific gravity of water)*(1/1000)
= (140/1)*(1/1000)
= 0.140`m^3`
e. Volume of admixture= (Mass of Chemical admixtures/Specific gravity of admixtues)*(1/1000)
= (7.6/1.145) *(1/1000) (Mass - 2% of 350 cementitious material = 7.6)
= 0.006`m^3`
f.Volume of Aggregate(FA&CA)= (a-(b+c+d+e))
= (1-(0.086+0.052+0.140+0.006))
= 0.716`m^3`
g. Mass of Coarse aggregate= Vol. of aggregate* Vol. of CA* Specific gravity of CA *1000
= 0.716*0.576*2.74*1000
= 1130kg/m^3`kg/m^3`
h. Mass of Fine aggregate= Vol. of aggregate* Vol. of FA* Specific gravity of FA*1000
= 0.716*0.424*2.74*1000
= 831`kg/m^3`
Step:9
i. Mix Proportion:
- Cement = 270`kg/m^3`
- Fly ash = 115`kg/m^3`
- Water = 140`kg/m^3`
- Fine aggregate = 831`kg/m^3`
- Coarse aggregate = 1130`kg/m^3`
- Chemical Admixture = 7`kg/m^3` (2% of cement)
- Water cement ratio = 0.4
| Cement | Fine aggregate | Coarse aggregate | Water |
| 350 | 831 | 1130 | 140 |
| 1 | 2.15 | 2.94 | 0.364 |
| MIX RATIO - 1:2.15:2.94 |
Srep :10
The slump shall be measured and the water content and dosage of admixturre shall be adjusted for achieving the required slump on trial. The mix proportion shall be reworked for the actual water content aand checked for durability requirements.
Step:11
Two or more trials having variation of 10% of water -cement ratio in clouse 10(Step-10) hall be carried out and graph between three water cement ratio and corresponding strenght shall be plotted to work out he mix proportions for the given target strenght for feild trials. However durability shall be met.
RESULT : THE MIX RATIO FOR M50 GRADE CONCRETE IS 1:2.15:2.94
: MIX DESIGN FOR M50 GRADE CONCRETE :
AIM :- Mix design for M50 grade concrete without fly ash.
INTRODUCTION OF CONCRETE MIX DESIGN:-Conrete mix design is a systematic process of choosing economical realative proportions of various ingredients from available material thar gives the concrete of desired workability. The process selecting suitable ingredients for producting concrete of required strenght durability , and workability as economical as possible is known as concrete Mix design.
Procedure:
Step:1
Stipulation For Proportioning:-
- Grade Designation : M50
- Type of Cement: OPC 43 grade (as IS-8112)
- Maximum nominal size of aggregate: 20mm
- Minimum Cement conctent : 320`kg/m^3`(From Table-5 of IS-456:2000, based on Exposure Condition)
- Maximum water cement ratio: 0.45 (From table-5 of IS-456:2000 , based on Exposure Condition)
- Workabillity: 100 mm slump value of pumpable concrete
- Exposure condition: Severe (For Reinforced Concrete)
- Method Of Concrete Placing: Pumping
- Degree Of Supervision: Good
- Type Of aggregate: Crushed Angular aggregate
- Maximum Cement Content: 450`kg/m^3`.
- Chemical Admixture: Superplasticizer
Step:2
Test Data For Materials:
- Cement used: OPC 43 grade (Confirming to IS-8112)
- Specific Gravity of Cement : 3.15
- Chemical Admixture : Superplasticizer (Confirming to IS-9103)
- Specific Gravity of:
- Fine Aggregate: 2.74
- Course Aggregate :2.74 - Water Absorption:
- FineAggregate: 1.0%
- Coarse Aggregate : 0.5% - Free Surface Moisture:
- Fine Aggregate: Nill
- Coarse Aggregate:Nill - Sieve Analysis:
Coarse Aggregate
Fine Aggregate (confirmig to grading Zone-1 of Table-4 of IS-383)
Step:3
To find Target Mean Strenght for mix proportioning:
Target mean Strenght f'ck = fck + 1.65*s
= 50+1.65*5
= 58.25 `N/mm^2`
Where,
fck-Charasteristics Compressive strenght
f'ck-Target Average Compressive Strenght at 28 days
S- Standard Deviation
From table-1 of IS-10262:2009, Standard Deviation S=`N/mm^2`
Step:4
Selection of Water cement ratio:
from table -5 456:2000 , Exposure Condition
here severe condition is considered , Maximum water- cement ratio = 0.45
Based on experience
On Experience water Cement ratio = 0.4
0.4< 0.45 hence OK.
Step:5
Calculation of Water Content:
Maximum Water content for 20mm aggregate = 186 litres(From table-2 of IS-10262:2009) for 25 mm to 50 mm slump range
for 100mm slump = 186 +(6/100)*186 = 197 litres
As superplasticizer is used the water content is reduced upto 30%
Based on trials water content reduction of 29% is achieved with plasticizer.
Hence arrived water content = 197*0.71= 140 litres
Step:6
Calculation of Cement content:
Water-Cement Ratio- 0.4
Cement Content = 140/0.4= 350`kg/m^3`
in table-5 of IS-456:2000, the cement content for sever Exposure = 320 `kg/m^3`
350 `kg/m^3`> 320`kg/m^3`
Hence OK.
Step:7
Proportion of coarse aggregate and fine aggregate content:
From table-3 of IS-10262:2009, volume of coarse aggregate correspondig to 20mm size aggregate and fine aggregate (Zone-1) for water cement ratio = 0.6
in Present case the water- cement ratio is 0.4
Therefore the volume of coarse aggregate needs to be increased to decrease the fine aggregate content.
As the water- cement ratio is lowered by 0.1 , the proportion of volume of coarse aggregate is increase by 0.02 (at the rate of +/-0.01 for every +/- 0.05 change in water cement ratio )
Hence the Corrected value of Coarse aggregate for water -cement ratio = 0.64
(If Coarse aggregate is not angular type , then also the volume of coarse aggregate may be required to be increased suitably , based on experience)
For pumpable concrete , these are reduced by 10%
volume of coarse aggregate = 0.64*0.9=0.576
volume of fine aggregate = 1-0.576= 0.424
MIX CALCULATION
- Volume of concrete - 1m^3
- Volume of cement = Volume of Cement = (Mass of cement/Specific gravity of cement) *(1/1000)
= (350/3.15)*(1/1000)
= 0.111`m^3`
c. Volume of water = (Mass/Specific gravity of water)*(1/1000)
= (140/1)*(1/1000)
= 0.140`m^3`
d. Volume of admixture= (Mass of Chemical admixtures/Specific gravity of admixtues)*(1/1000)
= (7.6/1.145) *(1/1000) (Mass - 2% of 350 cementitious material = 7.6)
= 0.006`m^3`
e.Volume of Aggregate(FA&CA)= (a-(b+c+d))
= (1-(0.111+0.140+0.006))
= 0.743`m^3`
f. Mass of Coarse aggregate= Vol. of aggregate* Vol. of CA* Specific gravity of CA *1000
= 0.743*0.576*2.74*1000
= 1173`kg/m^3`
g. Mass of Fine aggregate= Vol. of aggregate* Vol. of FA* Specific gravity of FA*1000
= 0.743*0.424*2.74*1000
= 863`kg/m^3`
h. Mix Proportion:
- Cement = 350`kg/m^3`
- Water = 140`kg/m^3`
- Fine aggregate = 863`kg/m^3`
- Coarse aggregate = 1173`kg/m^3`
- Chemical Admixture = 0.006`kg/m^3`(2% of cement)
- Water cement ratio = 0.4
| Cement | Fine aggregate | Coarse aggregate | Water |
| 350 | 863 | 1173 | 140 |
| 1 | 2.46 | 3.35 | 0.4 |
MIX PRPORTION RATIO 1:2.46:3.35
Srep :10
The slump shall be measured and the water content and dosage of admixturre shall be adjusted for achieving the required slump on trial. The mix proportion shall be reworked for the actual water content aand checked for durability requirements.
Step:11
Two or more trials having variation of 10% of water -cement ratio in clouse 10(Step-10) hall be carried out and graph between three water cement ratio and corresponding strenght shall be plotted to work out he mix proportions for the given target strenght for feild trials. However durability shall be met.
RESULT : THE MIX RATIO FOR M50 GRADE CONCRETE IS 1:2.46:3.35
Tables used are :
Table-1 of IS-10262:2009 ( Standard deviation)
| S.no. | Grade | Standard deviation | N/mm^2 |
| 1 | M10 | 3.5 | N/mm^2 |
| 2 | M15 | 3.5 | N/mm^2 |
| 3 | M20 | 4 | N/mm^2 |
| 4 | M25 | 4 | N/mm^2 |
| 5 | M30 | 5 | N/mm^2 |
| 6 | M35 | 5 | N/mm^2 |
| 7 | M40 | 5 | N/mm^2 |
| 8 | M45 | 5 | N/mm^2 |
| 9 | M50 | 5 | N/mm^2 |
TABLE-5
Minimum cement content , Maximum Water cement ratio and Minimum Grade of concrete for diffent exposure with Normal weight aggregate of 20mm Nominal Size
Exposure Plain Concrete Reinforced concrete
| S.No. | minimum cement content `kg/m^3` | maximum free water-cement ratio | minimum grade of concrete | minimum cement content `kg/m^3` | maximum free water cement ratio | minimum grade of concrete | |
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) |
| a. | Mild | 220 | 0.60 | -- | 300 | 0.55 | M20 |
| b. | Moderate | 240 | 0.60 | M15 | 300 | 0.50 | M25 |
| c. | severe | 250 | 0.50 | M20 | 320 | 0.45 | M30 |
| d. | very severe | 260 | 0.45 | M20 | 340 | 0.45 | M35 |
| e. | Extream | 280 | 0.40 | M25 | 360 | 0.40 | M40 |
Table-2 of IS 10262:2009
| S. no. | Nominal mzximum size of aggregate(mm) | Maximuum water content (kg) |
| 1. | 10 | 208 |
| 2. | 20 | 186 |
| 3. | 40 | 165 |