Mix Design Concrete Thumb Rules Engineer Should Know

Concrete Mix design is complete science and it is based on a lot of research. Popular Mix Design method is highlighted in the  ACI 2011 of committee report. It is a systematic approach in which user starts with defined slump and strength and some other parameters. End result gives quantities of different constituents.

Mix Design Concrete Thumb Rules Engineer Should Know

Performance-based methods are also available in which engineer based on his experience selects initial proportions and modifies as needed. Both systematic and performance-based methods have certain advantages and disadvantages which will be covered in later posts.
Though the mix design is the comprehensive processes still it is of  very useful for the engineer to know certain mix design concrete thumbs rules which will make his life easier. Here is the list

Mix design gives concrete constituents which include coarse aggregate, fine aggregate, cement and water.

By adding the 1 litre of water in one cubic meter of concrete mix

Increase slump of about 25 mm is expected.
It will decrease the  compressive strength of about 1.5 to 2.0 N/mm2
Increase the shrinkage potential of about 10%
Waste as much as ¼ bag of the  cement

Effect of increasing the concrete mix temperature by 1 celsius

About 4 liters of water per cubic meter maintains the equal slump
Air content decreases about the 1%
Compressive strength decreases about from 1.0 to 1.5 N/mm2

Effect of air content on concrete mix 

If the air content increases 1%, it will result in the compressive strength decrease about 5%
If air content decreases by 1%, then it will the cause yield to decrease about the 0.03 cubic meter per 1 cubic meter of concrete mix.
If air content decreases 1%, then slump ofdecrease about 12.5 mm
If air content decreases 1%, it will result in the durability decreases of about 10%.