A site engineer needs to know some of the fundamental thumb rules, which one can apply directly at the site without compromising the strength. Under simple circumstances and situations where we have a margin of strength, one can use these thumb rules.
However, it is very important to keep in mind that for structures demanding high strength and durability, we will not recommend to use these thumb rules for concrete mix design instead follow the concrete mix design procedure as per IS codal provisions. As the quantity of materials depends largely on the different parameters like exposure condition, workability, strength, the water-cement ratio etc., it is always recommended to follow the concrete mix design procedure for efficient and durable construction.
You want a tip for easy and fast execution at site……
Yes, then you can definitely use these Thumb rules……
Thumb Rules to determine the quantity of materials for a particular grade of Concrete Mix.
Grade of Concrete – M10 ( 1 : 3 : 6 )
| Cement | 220 kg |
| Fine Aggregate | 608 kg |
| Coarse Aggregate | 1170 kg |
| Water | 114 kg |
Grade of Concrete – M15 ( 1 : 2 : 4 )
| Cement | 315 kg |
| Fine Aggregate | 579 kg |
| Coarse Aggregate | 1114 kg |
| Water | 156 kg |
Grade of Concrete – M20 ( 1 : 1.5 : 3 )
| Cement | 401 kg |
| Fine Aggregate | 552 kg |
| Coarse Aggregate | 1064 kg |
| Water | 194 kg |
Concrete Mix Design
- Calculate cement, sand and aggregate quantity in concrete.
- Calculate the number of premix bags required for your project.
- Option to set your own size and rate of premix bags.
- Calculate the volume of concrete required for slabs, walls, footings and columns.
- Calculate the weight of ingredients required for preparing the calculated volume of concrete.
Grade of Concrete – M25 ( 1 : 1.0 : 2 )
| Cement | 551 kg |
| Fine Aggregate | 506 kg |
| Coarse Aggregate | 975 kg |
| Water | 260 kg |
The Effect of Air Content in Concrete Mix : Thumb Rules
| Air Content | |
|---|---|
| Increased by 1 % | Compressive Strength- Decreased by 5 % |
| Decreased by 1 % | Slump Value – Decreased about 12.5 mm |
| Decreased by 1 % | Durability – Reduced by 10 % |
These are some of the very important thumb rules.
You can implement these tips for constructions of less important structures. For structures where strength and durability is a primary factor, we should always follow the concrete design procedure as per IS: 456:2000 and IS:10262:2009.
If you want to go through the detailed procedure of concrete mix design as per IS codes. Go through this “Concrete mix design procedure as per IS 10262:2009 & IS 456:2000“