## Steps Involved in Mix Proportioning as per IS 10262:2009 (with solved example)

**General Steps Involved in Mix Proportioning**

**Step 1. Choice of Slump**

- Stiffest possible consistency that can be easily placed and compacted without segregation
- Pumping are typically designed for 100 mm to 150 mm slump

**Step 2. Choice of Max. Size of Aggregate**

- For given volume of coarse aggregate,

**Step 3. Estimation of the mixing water content and air content**

Depends on ,

- The maximum particle size of the aggregate
- Entrained air

**Step 4. Selection of water-cement ratio**

- Develop the relationship between strength and water-cement ratio for the materials to be used actually
- Checked for durability criteria

**Step 5: Calculation of the cement content**

- Computed by dividing the mixing water content by the water-cement ratio
- Adjustments to Min. cement content for aggregates other than 20 mm nominal max. size, as per IS 456: 2000

**Step 6: Estimation of the coarse aggregate content**

- Estimated from Maximum aggregate size & fineness modulus of fine aggregate
- Dry weight obtained by multiplying with Dry Rodded unit weight
- Range in proportions of materials used in concrete, by absolute volume

**Step 7: Estimation of the fine aggregate content**

- Weight Method
- Absolute volume Method

**Step 8: Adjustments for the aggregate moisture**

- Mixing water reduced depending on Free Moisture
- Amounts of aggregates increased accordingly

**Step 9: Trial batch adjustments**

- Mixture satisfying the desired criteria of workability and strength is obtained
- Mixture proportions of the laboratory-size trial batch are scaled up for producing full-size field batches

**Data required for Proportioning**

Road Aggregates

- Grade Designation
- Type of Cement
- Maximum Nominal size of Aggregate
- Minimum Cement Content
- Maximum w/c ratio
- Workability in terms of Slump
- Exposure conditions
- Method of placing
- Type of aggregate
- Maximum cement content
- Test data of Materials
- Admixture type and condition of use if any

**Mix Proportioning as per IS 10262:2009**

- Target strength for mix proportioning
- Selection of w/ c ratio
- Selection of water content
- Corrections in water content
- Calculation of cement content
- Proportion of volume of coarse aggregate and fine aggregate content
- Corrections
- Mix calculations

**Design stipulations for proportioning**

- Grade designation : M20
- Type of cement : OPC 43 grade, IS 8112
- Max. nominal size of agg. : 20 mm
- Minimum cement content : 320 kg/m3
- Maximum water cement ratio : 0.55
- Workability : 75 mm (slump)
- Exposure condition : Mild
- Degree of supervision : Good
- Type of agg. : Crushed angular agg.
- Maximum cement content : 450 kg/m3
- Chemical admixture : Not used

Very good website I would like recommend to my students and also would contribute…

You can find online concrete mix design following IS 10262 at http://www.concretemixdesign.net/