**M20 grade of concrete and their mix ratio ****,**hi guys in this article we know about grade of concrete and m20 grade of concrete mix ratio and ratio of grade of concrete like m5, m 7.5, m10, m15, m 20, m25 and so more.

There are two types of concrete plain cement concrete (PCC) and reinforcement cement concrete (RCC). Plain cement concrete is without use of reinforcement and reinforcement cement concrete is presence of reinforcement in concrete.

So grade of concrete like M5, M7.5, M10 and M15 are used in plain cement concrete and M20 and M25 and higher grade of concrete is used in RCC work like formation of support structure like footing, Foundation ,column, beam and compressive structure life slab.

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**Grade of concrete**

Grade of concrete is classified into 3 category according to mix proportion cement sand and aggregate and ratio of grade of concrete. And ratio of grade of concrete.

grade of concrete are categorized into nominal grade of concrete, standard grade of concrete and high strength concrete.

**nominal mix grade of concrete**

grade of concrete like m5, m 7.5,m10,m15, m 20 are called as nominal mix grade of concrete

**standard grade of concrete**

grade of concrete like m25, m 30, m 35, m 40, m 45 are called as standard grade of concrete

**high strength grade of concrete**

the grade of concrete like m50 ,m55,m60,m65,m70 are known as high strength concrete.

**What is characteristic compressive strength of grade of concrete**

Strength of concrete commonly known as characteristics compressive strength and it is represented by fck. Fck of different grade of concrete is represented as like m5, m 7.5,m10,m15, m 20. In which m is stand for concrete mix design and numerical figure 5,7.5 ,10, 15 and 20 is characteristics compressive strength of concrete after 28 days of casting and curing time generally it is represented as 5 N/mm2, 7.5N/mm2, 10N/mm2, 15N/mm2 , 20N/mm2 respectively.it means fck value for m20 grade of concrete is 20 N/mm2.

Compressive strength of grade of concrete such as M5,M7.5,M10,M15,M20 are 5 N/mm2,7.5 N/mm2,10 N/mm2,15 N/mm2 and 20 N/mm2 respectively.

**Concrete mix ratio of different grade of concrete**

Different grade of concrete have different concrete mix ratio . nominal mix of grade of concrete having general proportion of sand cement and aggregate and it is not decided by design mix. it is generally used in in construction of residential building. Simple grade of concrete is m5, m 7.5,m10,m15, m 20 having decided grade of concrete mix ratio according to their nominal mix.

What is standard grade of concrete and high strength concrete decided according to concrete mix design. Concrete mix design is the process of finding right proportion of cement sand and aggregate for concrete to achieve target strength in a structure.

The concrete mix design involves various steps Calculation and laboratory test to find Right Mix proportion. And benefits of concrete mix design is that it provides the right proportional material making the concrete construction economical in as required characteristics of compressive strength of structural member. But me give here concrete mix ratio for different grade of concrete.

1) m5 grade of concrete mix ratio is 1:5:10,mixture of cement, sand and aggregate in which one part is cement, 5 Part is sand and 10 part is aggregate.

2) m7.5 grade of concrete mix ratio is 1:4:8,mixture of cement, sand and aggregate in which one part is cement 4 Part is sand and 8 part is aggregate.

3) m10 grade of concrete mix ratio is 1:3:6,mixture of cement, sand and aggregate in which one part is cement, 3 Part is sand and 6 part is aggregate.

4) m15 grade of concrete mix ratio is 1:2:4, mixture of cement, sand and aggregate in which one part is cement, 2 Part is sand and 4 part is aggregate.

5) m20 grade of concrete mix ratio is 1:1.5:3, mixture of cement, sand and aggregate in which one part is cement, 1.5 Part is sand and 3 part is aggregate.

6) m25 grade of concrete mix ratio is 1:1:2, mixture of cement, sand and aggregate in which one part is cement, 1 Part is sand and 2 part is aggregate.

**M20 grade of concrete**

M20 grade of concrete is minimum nominal mix of concrete which is used in RCC work of construction of building structural member like compressive member footing, foundation and column and flexural member like beam and slab.

M20 concrete of grade represents M stands for concrete mix design and 20 numerical figure is their characteristics of compressive strength gain in 28 days after casting and proper curing. Their fck value or characteristics of compressive strength is 20 N/mm2.

**M20 grade of concrete mix ratio**

M20 grade of concrete ratio is 1 : 1.5 : 3, mixture of cement, sand and aggregate in which one part is cement, 1.5 part is sand and 3 part is aggregate or stone.

It means 1 bag of cement mixed with 1.5 bag of sand and three bag of aggregate to make concrete mix of M20 grade of concrete.

**Calculate quantity of cement sand and aggregate in 1m3 of m20 grade of concrete**

As we know that during concreting when we place wet concrete its gets hardened after certain standard time 30 minute to 10 hours and voids of concrete is completely evaporated so there is decrease in their volume and there volume is decrease by about 54% it means dry volume of concrete is increased by 54%

We have given Volume of wet concrete = 1m3

And we know that dry volume of concrete is 1.54 times of wet concrete volume

So dry volume of concrete = 1.54 m3

It means 1.54 cubic metre of dry composition of cement sand and aggregate is required to casting of wet concrete 1 cubic metre when it is add with water.

M20 concrete ratio = 1 : 1.5 : 3

Sum of grade of concrete ratio = 1+1.5+3 =5.5

1) **Volume of aggregate** = (3/5.5)×1.54 m3

Volume of aggregate = 0.84 m3

1m3 = 35.32 cft

Volume of aggregate = 0.84×35.32 cft

Volume of aggregate = 29.67 cft

2) **volume of sand** = (1.5/5.5)×1.54 m3

Volume of sand = 0.42 m3

1 m 3 = 35.32 cft

Volume of sand in cft = 0.42×35.32 cft

Volume of sand in cft = 14.83 cft

3) **Volume of cement** =( 1/5.5)×1.54 m3

Volume of cement = 0.28 m3

Density of cement = 1440 Kg/m3

Weight of cement in Kg = 1440×0.28 Kg

Weight of cement = 403 kg

Weight of one bag cement = 50 kg

Bag of cement = 403/50 =8 bag cement