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M20 Concrete Ratio is the most commonly used concrete in the construction of small-scale building structures. In the field, I used to suggest using the M20 concrete ratio for small to medium-sized structures for cost control. For e.g. If a small building has to be constructed whose height does not exceed 3 floors, I mostly suggest using M20 concrete.
For RCC work, I suggest using M20 or richer grade only. I have seen problems like corrosion of steel and cracking when M15 or smaller grade concrete is used.
For heavy structures like a dam, buildings with a height of more than 3 floors, airport construction, highway construction, and other similar construction, I mostly suggest using M25 or richer concrete grade.
1. Calculate Cement, Sand & Aggregate for M15 Concrete
2. M20 Concrete Ratio – Overview
M20 concrete ratio is 1:1.5:3. It indicates the cement:sand: aggregate ratio. It simply means that if 1 kg of cement is used for making Concrete, you should use 1.5 kg of sand and 3 kg of aggregate. ( i.e. 1 part cement: 1.5 parts sand: 3 parts aggregate ).
✔ In M20 concrete,
“M” stands for Mix ratio of cement:sand: aggregate & “20 “Stands for Compressive Strength @ 28 Days in N/mm².
| Code | Indian Standard 10262(2009). |
| Ratio | 1:1.5:3 |
| Compressive Strength | 20 MPa { Note: MPa = N/mm²} |
| Uses | Used in RCC works like; a. Rigid Pavement Construction b. Used to construct structural members like slabs, beams, columns, etc. (for small to medium structures only. Not suitable for heavy structures or work). c. Water-retaining structures, piles, etc. |
| Grade Category | Normal Grade ( Nominal Mix ) |
| Required Water Cement Ratio | a. For high-quality concrete works; 0.45 w/c ratio is specified. b. Minimum water-cement ratio: 0.45 c. Maximum water-cement ratio: 0.50
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3. M20 Concrete Ratio Uses
This concrete grade is commonly used for small- to medium-scale constructions. Some common uses of the M20 Concrete Ratio are:
✔ Used in the construction of water-retaining structures.
✔ Used to construct piles and other general RCC structures.
✔ Used to build retaining walls, buildings, landscaping & architectural designs, etc.
4. Cement Sand Aggregate Calculation For 1 m³ M20 Concrete Ratio
Data per 1 m³ of M20 Concrete Ratio
| Material | Volume Required (m3) | Materials Required in kg |
| Cement | 0.28 | 403.2 |
| Fine Aggregate | 0.42 | 619.85 |
| Coarse Aggregate | 0.84 | 1359.82 |
| Water | 0.190 | 190 kg ( Average ) |
| Things To Know!! Density of Cement = 1440 kg/m3 Density of Sand = 1450-1500 Kg/m3 Density of Aggregate = 1450-1550 Kg/m3 Weight of Cement in 1 Bag = 50 Kg Volume of 1 Bag of Cement in Cubic meter = 0.03472 m3 |
Now, Taking
Grade of Concrete = M20 Concrete
Mix Ratio = 1:1.5:3
Total sum of ratio =1+1.5+3 =5.5
Wet volume of Concrete = 1 m3.
To get dry volume, wet volume increased by 54%
Dry volume of concrete = 1 + 0.54 = 1.54 m³
i. Cement Quantity Calculation
Quantity of cement = (Own Ratio/ Total sum of ratio) * Dry Volume
= ( 1/5.5 ) * 1.54
= 0.28 m³
Cement in kg = volume of cement * density of cement
= 0.28 * 1440
= 403.2 kg
ii. Sand Quantity Calculation
Quantity of sand = (Own Ratio/ Total sum of ratio) * Dry Volume
= ( 1.5/5.5 ) * 1.54
= 0.42 m³
iii. Aggregate Quantity Calculation
Quantity of aggregate = (Own Ratio/ Total sum of ratio) * Dry Volume
= ( 3/5.5 ) * 1.54
= 0.84 m³
iv. Water Calculation
For inferior-quality concrete: W/C ratio = 0.5
For superior-quality concrete: W/C ratio = 0.45
Minimum amount of water required per m³ = 0.45 * 403.2 = 181.44 kg
Maximum amount of water required per m³ = 0.5 * 403.2 = 201.6 kg
✔ M20 Concrete is nominal Concrete that can be skillfully prepared using Indian Standard IS 456:2000.
✔ Normally, about 38% of water is required for the complete hydration of Concrete.
As per Indian Standard IS 456:2000 for nominal mix ( i.e., M10, M15…, M25), the w/c ratio varies from 0.4 to 0.6.
For M20 Concrete, commonly w/c ratio of 0.45 to 0.50 is used.
4. References |
| Read Also: Grades of Concrete |
| Verified Article By Er. Madhu Krishna Poudel |
