Project on Concrete Mix Design for various grades of Concrete
Aim:Calculation of various concrete mix designs with and without fly ash.
Objective1:To calculate the concrete mix design for M35 grade concrete with flyash
Data specification:
| CEMENT |
| Type of cement | OPC 43 Grade |
| Sp Gr of cement | 3.15 |
| Max cement content | IS 456:2000 cl.8.2.4.2 |
| SITE CONDITIONS |
| Exposure | Severe |
| Workability | 100mm |
| Method of placing | Pumping |
| Degree of supervision | Good |
| ADMIXTURE |
| Mineral Admixture | Flyash 30% |
| Sp Gr | 2.2 |
| Chemical admixture | Super plasticizer(1%) |
| Sp Gr of chemical admixture | 1.145 |
| Pozzolona material | - |
| Sp Gr of pozzolona | - |
| AGGREGATES |
| PROPERTY | COARSE AGGREGATE | FINE AGGREGATE |
| Sp Gr | 2.46 | 2.73 |
| Mx nominal size =20mm |
Step 1: To determine the target strength using formula
ft=fck+1.65S
where ft is the target strength
fck=compressive strength of the concrete
S= standard deviation according to the grade of concrete from table1 of IS 10262:2019
Therefore,
ft= 35+(1.65*5)
=43.25N/mm^2
Step2: Selection of water cementious ratio
From the above fig. since target strength is less than 53 and greater than 43 N/mm^2 therefore curve 2 is taken which gives the water cementitious ratio to be 0.38
Now comparing this value with exposure condition values in the table 5 of IS 456:2000 max water cementicious value shouldnt exceed 0.45
Thus 0.38 is OK
Step 3: Calculation of water content
As per cl 4.2 of table 2 IS 10262:2019
For 20mm nominal aggregate size,max water content = 186l and this is for the slump value of 50mm
For an increase of slump by 25mm 3% is added to the value
Here our workability is 100mm so the water content comes out to be
186+6%of 186= 197l
For 1% of super plasticizer used,Water content is reduced to 20-30%,supposing the reduction in the water content is 23%
197-23%of 197
=152l
Step 4: Calculation of cementicious content:
Cementicious content=Water content/w c ratio
= 152/0.38
=400kg/m^3
As per table 5 of IS 456:2000 min cementecious content should not lower 320 kg/m^3
Hence ok
Since cementecious material consists of both cement and fly ash , we need to know the individual quantities of both.
From 5.4.1 in IS 10262:2019,which says "If flyash is 20% or more then the cementicious content is increased by 10%"
ie, 400*1.1=440kg/m^3
Increased cementecious content changes the water cement ratio
w/c= 152/440
= 0.34
Flyash is supposedly given as 30% therefore flyash content=30%*440
=132kg/m^3
Therefore cement content= 440-132= 308kg/m^3<450kg/m^3
Hence ok
Step5: Proportion of vol coarse and fine aggregate
Here we ned to find the zones given in table 3,clause 4.4 of same IS code
Finding the zone:First we need to know the max nominal size of aggregate ie 20mm in this case.Now referring to table 7,clause 6.1 and 6.2 Coarse Aggregate,for 20mm size aggregate 85-100% of the particles should pass through 20mm seive and referring to table 9 Fine aggregates clause 6.3, 85-100% comes in zone II. Hence taking zone II where the wc ratio comes out to be 0.62
Now referring to table 3,clause 4.4 of same IS code vol of coarse aggregate per unit vol of total aggregate for different zones of fine aggregate for wc ratio of 0.50 but since our water cement ratio is 0.34
Vol of CA= 0.62+((0.5-0.34)/0.05)*0.01
=0.652
When we use pumping,we reduce vol of CA by 10% for a better workability
=0.652*0.9
=0.586
Therefore fine aggregate vol.=1-0.586
=0.413
Step6: Mix calculations
| Total volume=1m^3 |
| Quantities | Mass(kg) | Sp gravity | Volume(m^3)(M/SG*1000) |
| Volume of water a | 152 | 1 | 0.152 |
| Vol of cement b | 308 | 3.15 | 0.09 |
| Vol of fly ash c | 132 | 2.20 | 0.06 |
| Vol of chem ad d | 1%of cementecious materials=4.4 | 1.145 | 0.0038 |
| Total volume of aggregates e= 1-(a+b+c+d)=0.7742m^3 |
| Total volume e | %of aggregate | sp gr | Mass(kg) | |
| Mass of CA | 0.7742 | 0.586 | 2.74 | 1243 |
| Mass of FA | 0.7742 | 0.413 | 2.65 | 847 |
REQUIRED QUANTITIES:
| CEMENT | 308kg |
| WATER CONTENT | 152l |
| WC RATIO | 0.34 |
| FLYASH | 132kg |
| SUPER PLASTICIZERS | 4.4kg |
| COARSE AGGREGATE | 1243kg |
| FINE AGGREGATE | 847kg |
Objective2: Calculation of M50grade concrete without flyash
Data specifications:
| CEMENT |
| Type of cement | OPC 43 Grade |
| Sp Gr of cement | 3.15 |
| Max cement content | IS 456:2000 cl.8.2.4.2 |
| SITE CONDITIONS |
| Exposure | Severe |
| Workability | 100mm |
| Method of placing | Pumping |
| Degree of supervision | Good |
| ADMIXTURE |
| Mineral Admixture | - |
| Sp Gr | 2.2 |
| Chemical admixture | Super plasticizer(1%) |
| Sp Gr of chemical admixture | 1.145 |
| Pozzolona material | - |
| Sp Gr of pozzolona | - |
| AGGREGATES |
| PROPERTY | COARSE AGGREGATE | FINE AGGREGATE |
| Sp Gr | 2.46 | 2.73 |
| Mx nominal size =20mm |
Step 1: To determine the target strength using formula
ft=fck+1.65S
where ft is the target strength
fck=compressive strength of the concrete
S= standard deviation according to the grade of concrete from table1 of IS 10262:2019
Therefore,
ft= 50+(1.65*5)
=58.25N/mm^2
Step2: Selection of water cementious ratio
From the above fig. since target strength is less than 53 and greater than 43 N/mm^2 therefore curve 2 is taken which gives the water cementitious ratio to be 0.34
Now comparing this value with exposure condition values in the table 5 of IS 456:2000 max water cementicious value shouldnt exceed 0.45
Thus 0.34 is OK
Step 3: Calculation of water content
As per cl 4.2 of table 2 IS 10262:2019
For 20mm nominal aggregate size,max water content = 186l and this is for the slump value of 50mm
For an increase of slump by 25mm 3% is added to the value
Here our workability is 100mm so the water content comes out to be
186+6%of 186= 197l
For 1% of super plasticizer used,Water content is reduced to 20-30%,supposing the reduction in the water content is 23%
197-23%of 197
=152l
Step 4: Calculation of cementicious content:
Cementicious content=Water content/w c ratio
= 152/0.34
=447kg/m^3
As per table 5 of IS 456:2000 min cementecious content should not lower 320 kg/m^3
Hence ok
Step5: Proportion of vol coarse and fine aggregate
Here we ned to find the zones given in table 3,clause 4.4 of same IS code
Finding the zone:First we need to know the max nominal size of aggregate ie 20mm in this case.Now referring to table 7,clause 6.1 and 6.2 Coarse Aggregate,for 20mm size aggregate 85-100% of the particles should pass through 20mm seive and referring to table 9 Fine aggregates clause 6.3, 85-100% comes in zone II. Hence taking zone II where the wc ratio comes out to be 0.62
Now referring to table 3,clause 4.4 of same IS code vol of coarse aggregate per unit vol of total aggregate for different zones of fine aggregate for wc ratio of 0.50 but since our water cement ratio is 0.34
Vol of CA= 0.62+((0.5-0.34)/0.05)*0.01
=0.652
When we use pumping,we reduce vol of CA by 10% for a better workability
=0.652*0.9
=0.586
Therefore fine aggregate vol.=1-0.586
=0.413
Step6: Mix calculations
| Total volume=1m^3 |
| Quantities | Mass(kg) | Sp gravity | Volume(m^3)(M/SG*1000) |
| Volume of water a | 152 | 1 | 0.152 |
| Vol of cement b | 447 | 3.15 | 0.14 |
| Vol of chem ad c | 1%of cementecious materials=4.47 | 1.145 | 0.0051 |
| Total volume of aggregates e= 1-(a+b+c)=0.2972m^3 |
| Total volume e | %of aggregate | sp gr | Mass(kg) | |
| Mass of CA | 0.2972 | 0.586 | 2.74 | 477 |
| Mass of FA | 0.2972 | 0.413 | 2.65 | 325 |
REQUIRED QUANTITIES:
| CEMENT | 447kg |
| WATER CONTENT | 152l |
| WC RATIO | 0.34 |
| SUPER PLASTICIZERS | 4.47kg |
| COARSE AGGREGATE | 477kg |
| FINE AGGREGATE | 325kg |