Today, we will discuss grades of concrete, concrete mix ratios, uses, and many other things related to grades of concrete. First, let me tell you what you mean by the word concrete.

Concrete Meaning

Concrete is the paste made by mixing Portland cement, sand, fine or coarse aggregates, and water proportionally. Its main purpose is to bind all the building materials together and enhance the strength of the structure. We can determine the strength of the concrete mix by the number of materials such as cement, sand, aggregates, and water used to prepare the mixture. Now, let’s dive into the grades of concrete.

Complete Guide on Grades of Concrete
Complete Guide on Grades of Concrete

What are the Grades of Concrete?

To make concrete, we mix all the ingredients such as cement, sand, fine and coarse aggregates, and water in a fixed proportion. Then, the mixture or paste is subjected to cast and placed in a cube of size 150 mm. After that, it is placed in a water bath for at least 28 days. Thereafter, it is subjected to the compression test. The result determined is the compressive stress of the concrete. This compressive stress is termed as Grades of Concrete. Its unit is N/mm².

You can find several grades of concrete in the market based on the proportions of materials used. These are M10, M20, M30, M35, and so on. Grades of Concrete are characterized by M10, M20, M30, etc as per their compressive strength. You might be thinking what does this M10 or M20 characterize.

Also Read : What Is Concrete With Definition & History


What do you mean by M10 or M20? What does it represent?

The letter “M” exemplifies mix or mixture.  Mix or mixture depicts concrete with its specified proportions of the building materials such as cement, sand, and fine or coarse aggregate. And the number such as 10 or 20 placed after the letter “M” depicts the compressive strength of that concrete mix. It is denoted by N/mm² after the water bath of 28 days.

Let’s take an example to understand in a better way. For instance, if we consider M20 grade of concrete mix, it exemplifies the compressive strength of the concrete after the water bath of 28 days is 20 N/mm².

Now, have a look at the Concrete Mix Design Table.


Concrete Mix Design Table

Here is the current chart table exhibiting several grades of concrete mix design along with their mixed ratios of cement, sand, and aggregates employed.

S.NGrades of ConcreteRatios of Concrete Mix DesignCompressive Strength (N/mm²)Psi
1.M51:5:105 N/mm²725
2.M7.51:4:87.5 N/mm²1087
3.M101:3:610 N/mm²1450
4.M151:2:415 N/mm²2175
5.M201:1.5:320 N/mm²2900
6.M251:1:225 N/mm²3625
7.M301:0.75:1.530 N/mm²4350
8.M351:0.5:135 N/mm²5075
9.M401:0.25:0.540 N/mm²5800
10.M45Design Mix45 N/mm²6525

High Strength Concrete Grades or Grades of high-performance concrete

S.N.Grades of ConcreteRatios of Concrete Mix DesignCompressive Strength (N/mm²)Psi
1.M50Design Mix50 N/mm²7250
2.M55Design Mix55 N/mm²7975
3.M60Design Mix60 N/mm²8700
4.M65Design Mix65 N/mm²9425
5.M70Design Mix70 N/mm²10150


According to the rules of IS 456:2000, the grade of concrete below M20 should not be utilized in any RCC works. M25 is considered as the standard grade of concrete.

You can recognize in the table, the quantity of aggregate is kept double of that old sand in these concrete mix designs. You can estimate these ratios by utilizing buckets or standard cubes during the construction project. It helps to maintain consistency.

You might be thinking of what should be the water content ratio in the concrete mix design.

Also Read : Different Types Of Concrete


Water content ratio in concrete mix

The water content ratio in the concrete mix design defines the workability and strength of the concrete. If you use an adequate amount of water, it increases the workability of concrete. But it decreases the strength of concrete. If you use less amount of water, workability reduces and it’s difficult to use such type of concrete in construction works. The quantity of water varies for the different grades of the concrete.

mix ratio of concrete
Mix Ratio of Concrete

What are the several types of concrete grades and their uses?

Selecting the proper concrete grade for the construction job is a difficult task. We are here to help you choose the best concrete grade for your construction projects. You might be curious to know where these grades of concrete can be used. Here we will discuss some of the grades of concrete and their uses in the construction job.

C5

C5 is utilized to provide the smooth surface to the foundation concrete and to stave off the direct touch of foundation concrete from the soil.

C7.5

C7.5 is utilized to provide the smooth surface to the foundation concrete and to stave off the direct touch of foundation concrete from the soil.

C10

C10 grade of concrete is basically utilized for Patio slabs, paths ys, and non-structural work.

C15

C15 is utilized for pavement curbs and floor binding works.

C20

C20 is utilized for both domestic floors and foundations. It is also used for workshop bases, garages, internal floor slabs.

C25

C25 is utilized for construction in all areas as it is considered as Standard Concrete. It is also known as the multi-purpose concrete mix, usually in foundations.

C30

C30 is mainly utilized for pathways and roadways. 

C35

C35 is mainly employed for commercial buildings. This heavy concrete mix design is basically used for building external walls and slabs along with structural piling.

C40

C40 is utilized for building foundations and beams for structural backing and roads.  

C45

C45 is utilized as RCC (Reinforced Cement Concrete) for runways, concrete roads, RCC columns, RCC beams, etc.

C50

C50 is utilized as RCC (Reinforced Cement Concrete) for runways, concrete roads, RCC columns, RCC beams, etc.

C55

C55 is utilized for Pressurised Concrete Girders and Pier.

C60

C60 is utilized for RCC work where high compressive strength is employed such as high-rise buildings, long-span bridges, etc.


Frequently Asked Questions

Which grade of concrete you can use for constructing the foundation?

C25 considered as standardized mix concrete or ST2 Concrete is widely used for foundations.

Which grade of concrete you can use for footings?

C25 considered as standard mix concrete or ST2 Concrete is widely employed for footings.

Which grade of concrete you can use for rigid pavement?

C15 is utilized for pavement herbs and C30 is used for the pathways and roadways. 

Which grade of concrete you can use for bridge construction?

C60 is utilized for RCC work where high compressive strength is employed such as long-span bridges, etc.

Which grade of concrete you can use for RCC columns?

C50 is utilized as RCC (Reinforced Cement Concrete) for RCC columns, RCC beams, etc.

How to find the grade of concrete?

To make concrete, we mix all the ingredients such as cement, sand, fine and coarse aggregates, and water in a fixed proportion. Then, the mixture or paste is subjected to cast and placed in a cube of size 150 mm.
After that, it is placed in a water bath for at least 28 days. Thereafter, it is subjected to the compression test. The result determined is the compressive stress of the concrete. This compressive stress is termed as Grades of Concrete. Its unit is N/mm².
You can find several grades of concrete in the market based on the proportions of materials used. These are M10, M20, M30, M35, and so on. Grades of Concrete are characterized by M10, M20, M30, etc as per their compressive strength. 

Which grade of concrete you can use for road construction?

C30 is mainly utilized for the construction of pathways and roadways. 

What do you mean by high strength and high-performance concrete?

High-strength concrete is specified based on its compressive strength at a provided duration whereas high-performance concrete is characterized based on execution criteria namely: 
1. High durability
2. High strength
3. High work-ability

What are the two typical components utilized in high-performance concrete?

The two typical components utilized in high-performance concrete are quartz flour and fiber.

What are the compositions of High-Performance Concrete?

The composition of HPC usually comprises of:
1. Cement
2. Water
3. Fine Sand 
4. Super-Plasticizer
5. Fly Ash
6. Silica Fume

Conclusion 


We expect that this blog post is informative and useful. And if you are curious to expand your knowledge related to civil engineering, then please visit our blog for more knowledge on the concrete types and related to other topics. Please don’t forget to give your feedback in our comment box. We will be glad to appreciate your viewpoints.

Also Read: Planning And Site Preparation For Concrete

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