Mix Design For Concrete

Mix Design For M35 Grade Of Concrete

The mix design for M35 Grade Of Concrete for pile foundations provided here is for reference purpose only. Actual site conditions vary and thus this should be adjusted as per the location and other factors.

Grade of Concrete : M35
Characteristic Strength (Fck) : 35 Mpa
Standard Deviation : 1.91 Mpa*
Target Mean Strength : T.M.S.= Fck +1.65 x S.D.
(from I.S 456-2000) = 35+ 1.65×1.91
= 38.15 Mpa

Test Data For Material:
Aggregate Type : Crushed
Specific Gravity 
Cement : 3.15
Coarse Aggregate : 2.67
Fine Aggregate : 2.62

Water Absorption:
Coarse Aggregate : 0.5%
Fine Aggregate : 1.0 %

MIX DESIGN

Take Sand content as percentage of total aggregates = 36%

Select Water Cement Ratio = 0.43 for concrete grade M35

(From Fig 2. of I.S. 10262- 1982)

Select Water Content = 172 Kg

(From IS: 10262 for 20 mm nominal size of aggregates Maximum Water Content = 186 Kg/ M)

Hence, Cement Content= 172 / 0.43 = 400 Kg / M3

Formula for Mix Proportion of Fine and Coarse Aggregate:

1000(1-a0) = {(Cement Content / Sp. Gr. Of Cement) + Water Content +(F/ Sp. Gr.* P)}

1000(1-a0) = {(Cement Content / Sp. Gr. Of Cement) + Water Content +C/ Sp. Gr.* Pc )}

Where C= Coarse Aggregate Content

F= Fine Aggregate Content

P= Sand Content as percentage of total Aggregates

= 0.36

Pc = Coarse Aggregate Content as percentage of total Aggregates.

= 0.64

a= Percentage air content in concrete (As per IS :10262 for 20 mm nominal size of

aggregates air content is 2 %) = 0.02

Hence, 1000(1-0.02) = {(400 /3.15) + 172 +(F/ 2.62 x 0.36)}

Fa = 642 Kg/ Cum

As the sand is of Zone II no adjustment is required for sand.

Sand Content = 642 Kg/ Cum

1000(1-0.02) = {(400 /3.15) + 172 +(C/ 2.67 x 0.64)}

Hence, Ca = 1165 Kg/ Cum

From combined gradation of Coarse aggregates it has been found out that the proportion of 53:47 of 20 mm & 10 mm aggregates produces the best gradation as per IS: 383.

Hence, 20 mm Aggregates = 619 Kg

And 10 mm Aggregates = 546 Kg

To obtain slump in the range of 150-190 mm water reducing admixture brand SP430 from Fosroc with a dose of 0.3 % by weight of Cement shall be used.

Hence the Mix Proportion becomes:

Cem W/C Water Sand 20mm 10mm Admix
400 0.43 172 635 619 564 1.2
1 0.43 1.6 1.547 1.36 0.003

Units – Kg/ M3

Cement : Sand: Coarse Aggregates = 1 : 1.6 : 2.907

We are thankful to Er. Ishan Kaushal for this valuable information.

 

Mix Design For M35 Grade Of Concrete

The mix design for M35 Grade Of Concrete for pile foundations provided here is for reference purpose only. Actual site conditions vary and thus this should be adjusted as per the location and other factors.

Grade of Concrete : M35
Characteristic Strength (Fck) : 35 Mpa
Standard Deviation : 1.91 Mpa*
Target Mean Strength : T.M.S.= Fck +1.65 x S.D.
(from I.S 456-2000) = 35+ 1.65×1.91
= 38.15 Mpa

Test Data For Material:
Aggregate Type : Crushed
Specific Gravity 
Cement : 3.15
Coarse Aggregate : 2.67
Fine Aggregate : 2.62

Water Absorption:
Coarse Aggregate : 0.5%
Fine Aggregate : 1.0 %

MIX DESIGN

Take Sand content as percentage of total aggregates = 36%

Select Water Cement Ratio = 0.43 for concrete grade M35

(From Fig 2. of I.S. 10262- 1982)

Select Water Content = 172 Kg

(From IS: 10262 for 20 mm nominal size of aggregates Maximum Water Content = 186 Kg/ M)

Hence, Cement Content= 172 / 0.43 = 400 Kg / M3

Formula for Mix Proportion of Fine and Coarse Aggregate:

1000(1-a0) = {(Cement Content / Sp. Gr. Of Cement) + Water Content +(F/ Sp. Gr.* P)}

1000(1-a0) = {(Cement Content / Sp. Gr. Of Cement) + Water Content +C/ Sp. Gr.* Pc )}

Where C= Coarse Aggregate Content

F= Fine Aggregate Content

P= Sand Content as percentage of total Aggregates

= 0.36

Pc = Coarse Aggregate Content as percentage of total Aggregates.

= 0.64

a= Percentage air content in concrete (As per IS :10262 for 20 mm nominal size of

aggregates air content is 2 %) = 0.02

Hence, 1000(1-0.02) = {(400 /3.15) + 172 +(F/ 2.62 x 0.36)}

Fa = 642 Kg/ Cum

As the sand is of Zone II no adjustment is required for sand.

Sand Content = 642 Kg/ Cum

1000(1-0.02) = {(400 /3.15) + 172 +(C/ 2.67 x 0.64)}

Hence, Ca = 1165 Kg/ Cum

From combined gradation of Coarse aggregates it has been found out that the proportion of 53:47 of 20 mm & 10 mm aggregates produces the best gradation as per IS: 383.

Hence, 20 mm Aggregates = 619 Kg

And 10 mm Aggregates = 546 Kg

To obtain slump in the range of 150-190 mm water reducing admixture brand SP430 from Fosroc with a dose of 0.3 % by weight of Cement shall be used.

Hence the Mix Proportion becomes:

Cem W/C Water Sand 20mm 10mm Admix
400 0.43 172 635 619 564 1.2
1 0.43 1.6 1.547 1.36 0.003

Units – Kg/ M3

Cement : Sand: Coarse Aggregates = 1 : 1.6 : 2.907

 

Mix Design M-40 Grade

The mix design M-40 grade for Pier (Using Admixture – Fosroc) provided here is for reference purpose only. Actual site conditions vary and thus this should be adjusted as per the location and other factors.

Parameters for mix design M40

Grade Designation = M-40
Type of cement = O.P.C-43 grade
Brand of cement = Vikram ( Grasim )
Admixture = Fosroc ( Conplast SP 430 G8M )
Fine Aggregate = Zone-II
Sp. Gravity Cement = 3.15
Fine Aggregate = 2.61
Coarse Aggregate (20mm) = 2.65
Coarse Aggregate (10mm) = 2.66
Minimum Cement (As per contract) = 400 kg / m3
Maximum water cement ratio (As per contract) = 0.45

Mix Calculation: –

1. Target Mean Strength = 40 + (5 X 1.65) = 48.25 Mpa

2. Selection of water cement ratio:-
Assume water cement ratio = 0.4

3. Calculation of cement content: –
Assume cement content 400 kg / m3
(As per contract Minimum cement content 400 kg / m3)

4. Calculation of water: –
400 X 0.4 = 160 kg Which is less than 186 kg (As per Table No. 4, IS: 10262)
Hence o.k.

5. Calculation for C.A. & F.A.: – As per IS : 10262 , Cl. No. 3.5.1

V = [ W + (C/Sc) + (1/p) . (fa/Sfa) ] x (1/1000)

V = [ W + (C/Sc) + {1/(1-p)} . (ca/Sca) ] x (1/1000)

Where

V = absolute volume of fresh concrete, which is equal to gross volume (m3) minus the volume of entrapped air ,

W = mass of water ( kg ) per m3 of concrete ,

C = mass of cement ( kg ) per m3 of concrete ,

Sc = specific gravity of cement,

(p) = Ratio of fine aggregate to total aggregate by absolute volume ,

(fa) , (ca) = total mass of fine aggregate and coarse aggregate (kg) per m3 of
Concrete respectively, and

Sfa , Sca = specific gravities of saturated surface dry fine aggregate and Coarse aggregate respectively.

As per Table No. 3 , IS-10262, for 20mm maximum size entrapped air is 2% .

Assume F.A. by % of volume of total aggregate = 36.5 %

0.98 = [ 160 + ( 400 / 3.15 ) + ( 1 / 0.365 ) ( Fa / 2.61 )] ( 1 /1000 )

=> Fa = 660.2 kg

Say Fa = 660 kg.

0.98 = [ 160 + ( 400 / 3.15 ) + ( 1 / 0.635 ) ( Ca / 2.655 )] ( 1 /1000 )

=> Ca = 1168.37 kg.

Say Ca = 1168 kg.

Considering 20 mm : 10mm = 0.6 : 0.4

20mm = 701 kg .
10mm = 467 kg .

Hence Mix details per m3

Cement = 400 kg
Water = 160 kg
Fine aggregate = 660 kg
Coarse aggregate 20 mm = 701 kg
Coarse aggregate 10 mm = 467 kg
Admixture = 0.6 % by weight of cement = 2.4 kg.
Recron 3S = 900 gm

Water: cement: F.A.: C.A. = 0.4: 1: 1.65: 2.92

Observation: –
A. Mix was cohesive and homogeneous.
B. Slump = 110mm
C. No. of cube casted = 12 Nos.
7 days average compressive strength = 51.26 MPa.
28 days average compressive strength = 62.96 MPa which is greater than 48.25MPa

Hence the mix is accepted.

Mix Design M-50 Grade

The mix design M-50 grade (Using Admixture –Sikament) provided here is for reference purpose only. Actual site conditions vary and thus this should be adjusted as per the location and other factors.

Parameters for mix design M50

Grade Designation = M-50
Type of cement = O.P.C-43 grade
Brand of cement = Vikram ( Grasim )
Admixture = Sika [Sikament 170 ( H ) ] Fine Aggregate = Zone-II

Sp. Gravity
Cement = 3.15
Fine Aggregate = 2.61
Coarse Aggregate (20mm) = 2.65
Coarse Aggregate (10mm) = 2.66

Minimum Cement (As per contract) =400 kg / m3
Maximum water cement ratio (As per contract) = 0.45

Mix Calculation: –

1. Target Mean Strength = 50 + ( 5 X 1.65 ) = 58.25 Mpa

2. Selection of water cement ratio:-
Assume water cement ratio = 0.35

3. Calculation of water: –
Approximate water content for 20mm max. Size of aggregate = 180 kg /m3 (As per Table No. 5 , IS : 10262 ). As plasticizer is proposed we can reduce water content by 20%.

Now water content = 180 X 0.8 = 144 kg /m3

4. Calculation of cement content:-
Water cement ratio = 0.35
Water content per cum of concrete = 144 kg
Cement content = 144/0.35 = 411.4 kg / m3
Say cement content = 412 kg / m3 (As per contract Minimum cement content 400 kg / m3 )
Hence O.K.

5. Calculation for C.A. & F.A.: [ Formula’s can be seen in earlier posts]-

Volume of concrete = 1 m3
Volume of cement = 412 / ( 3.15 X 1000 ) = 0.1308 m3
Volume of water = 144 / ( 1 X 1000 ) = 0.1440 m3
Volume of Admixture = 4.994 / (1.145 X 1000 ) = 0.0043 m3
Total weight of other materials except coarse aggregate = 0.1308 + 0.1440 +0.0043 = 0.2791 m3

Volume of coarse and fine aggregate = 1 – 0.2791 = 0.7209 m3
Volume of F.A. = 0.7209 X 0.33 = 0.2379 m3 (Assuming 33% by volume of total aggregate )

Volume of C.A. = 0.7209 – 0.2379 = 0.4830 m3

Therefore weight of F.A. = 0.2379 X 2.61 X 1000 = 620.919 kg/ m3

Say weight of F.A. = 621 kg/ m3

Therefore weight of C.A. = 0.4830 X 2.655 X 1000 = 1282.365 kg/ m3

Say weight of C.A. = 1284 kg/ m3

Considering 20 mm: 10mm = 0.55: 0.45
20mm = 706 kg .
10mm = 578 kg .
Hence Mix details per m3
Increasing cement, water, admixture by 2.5% for this trial

Cement = 412 X 1.025 = 422 kg
Water = 144 X 1.025 = 147.6 kg
Fine aggregate = 621 kg
Coarse aggregate 20 mm = 706 kg
Coarse aggregate 10 mm = 578 kg
Admixture = 1.2 % by weight of cement = 5.064 kg.

Water: cement: F.A.: C.A. = 0.35: 1: 1.472: 3.043 

Observation: –

A. Mix was cohesive and homogeneous.
B. Slump = 120 mm
C. No. of cube casted = 9 Nos.
7 days average compressive strength = 52.07 MPa.
28 days average compressive strength = 62.52 MPa which is greater than 58.25MPa
Hence the mix accepted.

Concrete Mix Design M-60

(a) DESIGN STIPULATION:-
Target strength = 60Mpa
Max size of aggregate used = 12.5 mm
Specific gravity of cement = 3.15
Specific gravity of fine aggregate (F.A) = 2.6
Specific gravity of Coarse aggregate (C.A) = 2.64
Dry Rodded Bulk Density of fine aggregate = 1726 Kg/m3
Dry Rodded Bulk Density of coarse aggregate = 1638 Kg/m3

Step-1
Calculation for weight of Coarse Aggregate:
From ACI 211.4R Table 4.3.3 Fractional volume of oven dry Rodded C.A for 12.5mm size aggregate is 0.68m3
Weight of C.A = 0.68*1638 = 1108.13 Kg/m3

Step-2
Calculation for Quantity of Water:
From ACI 211.4R Table 4.3.4
Assuming Slump as 50 to 75mm and for C.A size 12.5 mm the Mixing water = 148 ml
Void content of FA for this mixing water = 35%
Void content of FA (V)
V = {1-(Dry Rodded unit wt / specific gravity of FA*1000)}*100
= [1-(1726/2.6*1000)]*100
= 34.62%

Adjustment in mixing water = (V-35)* 4.55
= (34.62 – 35)*4.55
= -1.725 ml
Total water required = 148 + (-1.725) = 146.28 ml
Step-3
Calculation for weight of cement
From ACI 211.4R Table 4.3.5(b)
Take W / C ratio = 0.29
Weight of cement = 146.28 / 0.29 = 504.21 kg/m3

Step-4
Calculation for weight of Fine Aggregate:

Cement = 504.21 / 3.15*1000= 0.1616
Water = 146.28 / 1*1000= 0.1462
CA = 1108.13 / 3*1000= 0.3690
Entrapped Air = 2 / 100= 0.020
Total = 0.7376m3
Volume of Fine Aggregate= 1-0.7376
Weight of Fine Aggregate= 0.2624*2.6*1000= 683.24 kg/m3

Step-5
Super plasticizer:
For 0.8% = (0.8 / 100)*583.53 = 4.668 ml

Step-6
Correction for water:
Weight of water (For 0.8%) =146.28 – 4.668 =141.61 kg/m3

Requirement of materials per Cubic meter
Cement = 504.21 Kg/m3
Fine Aggregate = 683.24 Kg/m3
Coarse Aggregate = 1108.13 Kg/m3
Water = 141.61 Kg/ m3
Super plasticizers = 4.6681 / m3

So the final ratio becomes
Cement : Fine agg (kg/m3) : Coarse agg (kg/m3) : Water (l/m3): Superplasticizer (l/m3)

1: 1.35 :2.19 :0.29 :0.8

This concrete mix design has been submitted to us by Natarajan. We are thankful to him for this valuable contribution.