Know all about different types of concrete and grades used in construction!
The minimal strength that concrete should have after 28 days of construction with good quality control is known as concrete quality. The prefix M is placed in front of the required MPa strength and denotes concrete quality. For instance, a 20 MPa concrete grade is designated as M20, where M stands for Mix. These concrete kinds are transformed into various mixing ratios. For M20 concrete, for instance, the concrete: Sand: Coarse Aggregate mixing ratio would be 1:1.5:3.
Based on the demands of the structural design, the kind of concrete construction is chosen. Concrete mixes come in two varieties: nominal mix and design mix. The nominal concrete mix is typically utilized in modest-sized commercial and residential structures when there is little need for concrete. The nominal mix protects several frequent quality control issues that arise during the building of concrete structures. Concretes with mixing ratios determined by numerous laboratory experiments are known as design concretes. When using shotcrete, quality control must be maintained during the selection of materials, mixing, transportation, and placement of the concrete. When the large-scale concrete building is done, this concrete gives mixing ratios based on locally accessible ingredients and reduces construction costs. Shotcrete is therefore utilized in substantial concrete building projects.
Therefore, based on the structural requirements, a suitable concrete quality may be chosen. In minor construction, nominal mixes for concrete grades like M15, M20, and M25 are frequently employed. Large constructions need to be extremely strong, thus greater grades of concrete, such as M30 and higher, are used. These concrete mixing ratios depend on the mix design.
The concrete kinds M15, M20, M25, etc. are typical types. M15 is often utilized for routine cement concrete work. The concrete class must be at least M20 for constructions made of reinforced concrete. MPa (N/mm2)psi mixed grade concrete compressive strength
Concrete Grade | Mix Ratio | Compressive Strength | |
MPa (N/mm2) | psi | ||
Normal Grade of Concrete | |||
M5 | 1: 5: 10 | 5 MPa | 725 psi |
M7.5 | 1 : 4 : 8 | 7.5 MPa | 1087 psi |
M10 | 1 : 3 : 6 | 10 MPa | 1450 psi |
M15 | 1 : 2 : 4 | 15 MPa | 2175 psi |
M20 | 1 : 1.5 : 3 | 20 MPa | 2900 psi |
Standard Grade of Concrete | |||
M25 | 1: 1: 2 | 25 MPa | 3625 psi |
M30 | Design Mix | 30 MPa | 4350 psi |
M35 | Design Mix | 35 MPa | 5075 psi |
M40 | Design Mix | 40 MPa | 5800 psi |
M45 | Design Mix | 45 MPa | 6525 psi |
High Strength Concrete Grades | |||
M50 | Design Mix | 50 MPa | 7250 psi |
M55 | Design Mix | 55 MPa | 7975 psi |
M60 | Design Mix | 60 MPa | 8700 psi |
M65 | Design Mix | 65 MPa | 9425 psi |
M70 | Design Mix | 70 MPa | 10150 psi |