Disclaimer: This calculator is intended for Educational purpose only and engineer should check the mix design manually before implementing on site.

- ‘*’ sign denotes required field quantities without which results will not be displayed.
- The mix design is calculated for crushed angular aggregates, any other shape of aggregate should be suitably adjusted in design.
- The mix design should be tested in laboratory as trial mix and suitable adjustments should be made for next trials if desired results are not achieved.
- This calculator shall only be used to design mix upto
**M65.** - For high strength concrete up to M90 kindly use this calculator.
- For tutorial on concrete mix design kindly check this video.

## Concrete Mix Design Calculator

## Mix Design Steps

### Step 1 : Target Mean Strength

In order that not more than the specified proportion of test results are likely to fall below the characteristic strength, the concrete mix has to be proportioned for higher target mean compressive strength f’ck. The margin over characteristic strength is given by the following relation:

fck′=fck+1.65 ∗S or

fck′=fck+X

where S and X are taken from IS 10262:2019

### Step 2: Approximate air content

Approximate amount of entrapped air is depended on nominal size of aggregate and is taken from the table 3 of IS 10262: 2019.

### Step 3 : Water - cement ratio

Water cement ratio for concrete mix design is taken from the graph given in figure 1 of IS 10262 – 2019.

The curve in the graph has to be selected based on grade of cement being used.

The maximum water cement ratio has to be checked from IS 456:2000 table number 5.

### Step 4 : Water Content

The water content is taken from Table 4 of IS 10262 – 2019 and is dependent on maximum nominal size of aggregates.

The water content is given form slump of 50mm and has to be suitably revised using the following formula:

wcx=wc50 +((x-50))/25∗3/100∗wc50

The water content can further be reduced based on the shape of the aggregates. 10kg reduction for sub angular aggregates, 15kg reduction for gravels with crushed aggregates and 20kg reduction for rounded gravels.

### Step 5 : Cement content

Cement content is calculated from the water cement ratio and the water content.

When using cement replacement like fly ash or ggbs, cement content shall be increased by 10%.

Maximum cement content from IS 456:2000 clause 8.2.4.2 has to be checked.

### Step 6 : Aggregates

The proportion of coarse aggregates out of total aggregates is taken from table 5 of IS 10262:2019.

The ratio depends on maximum nominal size of aggregate and the zone of fine aggregate.

The maximum nominal size of aggregate has to be taken from Table 7.