What is Nominal Mix and Design Mix ? and their Difference
We hope you all know that Nominal Mix is site level mixing and Design mix are designed from RMC plant.
You are right… But there are more than that.
Definition for Nominal Mix
Nominal Mix, we produce at site level are a volumetric basis.
These are established through observations at the site level for small quantity where load calculation are not necessary. We don’t actually find the specific gravity of cement, silt content of sand and the weight proportions etc.
We hope you actually don’t need to be so accurate for a sump cover.
So if we said 1:1.5:3 Ratio means that we have to weigh them to 1 kg of cement, 1.5 kg of fine aggregate and 3 kg of coarse aggregate.
But we normally take them on the volume basis and multiply them with 1.55 constant (in Nominal Mix Concrete Calculation) to get the bulk volume of the material.
Definition for Design Mix
Meanwhile, in Design mix, We produce them in weight basis especially for large volume where the load is important. We have to check each and every property of the ingredients.
- Weight of each ingredient
- Mix Proportions
- Type of exposure
- Properties of Cement
Initial & Final Setting Time
- Properties of Fine & Coarse Aggregates
Based on the above things, we will establish the mix design according to our needs and then check them with trail mix.
Once the trial mix has been tested and passed on 7th & 28th Days for compressive strength. Then it will be approved for batching and execution at the site level.
You can refer your site’s Quality Controller.
Source – IS 456:2000
Hope you enjoyed the Quick Tip.
Happy Learning 🙂