Project on Concrete Mix Design for various grades of Concrete

To design concrete mixes, we'll follow the guidelines provided by the indian standard (IS) codes. For this task, we'll use IS 10262:2019 for mix design.

M35 Grade Concrete With Fly Ash:

Given Data:

• Characteristic Compressive Strength: 35Mpa
• Type of cement: OPC 53 grade 
• Maximum size of Aggregate: 20 mm
• Zone of sand : zone 2 (as per IS 383) 
• Specific Gravity of cement : 3.15
• Specific Gravity of fly ash : 2.25
• Water-Cement Ratio: 0.45

Step 1: Target strength calculation:

The target mean strength is calculated using the formula:

fck = fck + 1.65 × s

where: 

• fck is the characteristic compressive strength.
• S is the standerd deviation which depends on the quality control.

For M35 grade concrete, fck = 35 Mpa.

Assuming standard deviation (S) as 5 Mpa (for good quality control), we get:

fck = 35 + 1.65 × 5 = 43.25 Mpa

Step 2: water-cement Ratio Calculation: 

As per IS 10262:2019, water-cement ratio formula is:

W/C = 0.45 + p/100 × 0.3/7 = 0.45+35/100 × 0.3/7 = 0.53

Step 3: selection of water content:

The water content is selected based on the desired workability. Lets assume its 185 kg/m⊃3;.

Step 4: Determination of cement content:

C = W/w/c = 185/0.53 = 349 kg/m⊃3;

Step 5: Determination of coarse and Fine Aggergate Content:

Let's assume a 20 mm maximum size of aggregate.

For 20 mm downgrade aggregates:

C.A. = 1- c/100 × 1/sp.gr.of coarse agg. = 1 - 349/100 × 1/2.67 = 0.887 m⊃3;

F.A. = 1 - C.A. = 1 - 0.887 = 0.113 m⊃3;

Step 6: Determination of Fly Ash Content:

Since we are using fly ash, we need to consider it in the mix design. Lets assume 20% replacement.

Fly Ash = 20/100 × C = 200/100 × 349 = 69.8 kg/m⊃3;

Step 7: Adjustments for Moisture Content:

Based on the moisture content, you may need to adjust the weights of aggregates and water.

M50 Grade concrete without Fly Ash:

• characteristic compressive strength: 50 Mpa 
• Type of Cement: OPC 53 grade
• Maximum Size of aggregate: 20 mm
• Zone of Sand: zone 2 (as per IS 383) 
• Specific Gravity of cement: 315
• Water-Cement ratio: 0.3 (assumed)

Step 1: Target Strength Calculation: 

The target mean strength is calculated using the formula:

Fck = Fck + 1.65 × S

For M50 grade concrete, fck = 50 Mpa.

Assuming standard deviation (S) as 5 Mpa (for good quality control), we get:

Fck = 50 + 1.65 × 5 = 58.25 Mpa 

Step 2: Water-Cement Ratio Selection:

As per IS 10262:2019, the water-cement ratio formula is: 

W/C = 0.3

Step 3: Selection of water content:

The water content is selected based on the desire workability. lets assume its 185 kg/m⊃3;.

Step 4: Determination of water ontent

C = W/W/C = 185/0.3 = 617 KG/m⊃3;

Step 5: Determination of coarse and Fine aggregate content:

lets assume a 20 mm maximum size of aggregrate.

C.A. = 1-C/100 ×  1/sp.gr.of coarse agg. = 1 - 617/100 × 1/2.67 = 0.787m⊃3;

F.A. = 1 - C.A. = 1- 0.787 = 0.213 M⊃3;

Step 6: Adjustments for moisture content:

Based on the moisture content, you may need to adjust the weights if aggregates and water.