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

**Specific 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 / m^{3}

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 /m^{3} (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 /m^{3}

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 / m^{3}

Say cement content = 412 kg / m^{3} (As per contract Minimum cement content 400 kg / m^{3} )

Hence O.K.

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

Volume of concrete = 1 m^{3}

Volume of cement = 412 / ( 3.15 X 1000 ) = 0.1308 m^{3}

Volume of water = 144 / ( 1 X 1000 ) = 0.1440 m^{3}

Volume of Admixture = 4.994 / (1.145 X 1000 ) = 0.0043 m^{3}

Total weight of other materials except coarse aggregate = 0.1308 + 0.1440 +0.0043 = 0.2791 m^{3}

Volume of coarse and fine aggregate = 1 – 0.2791 = 0.7209 m^{3}

Volume of F.A. = 0.7209 X 0.33 = 0.2379 m^{3} (Assuming 33% by volume of total aggregate )

Volume of C.A. = 0.7209 – 0.2379 = 0.4830 m^{3}

Therefore weight of F.A. = 0.2379 X 2.61 X 1000 = 620.919 kg/ m^{3}

Say weight of F.A. = 621 kg/ m^{3}

Therefore weight of C.A. = 0.4830 X 2.655 X 1000 = 1282.365 kg/ m^{3}

Say weight of C.A. = 1284 kg/ m^{3}

Considering 20 mm: 10mm = 0.55: 0.45

20mm = 706 kg .

10mm = 578 kg .

Hence Mix details per m^{3}

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.