Use of different grades of concrete, their strength and selection for c

What is concrete grade?

Concrete quality is defined as the minimum strength that concrete must have after 28 days of construction with adequate quality control. The quality of the concrete is indicated by advancing M to the desired strength in MPa. For example, for a concrete quality with a strength of 20 MPa, it is called M20, where M means mixture. This type of concrete is converted into different proportions of mixing. For example, for M20 concrete, the mixing ratio is 1:1. 5:3 for cement: sand: coarse aggregates.

How to choose a suitable grade of concrete for construction

The quality of concrete construction is selected based on structural design requirements. There are two types of concrete mix 

• Nominal mix.
• Building mix.

Nominal Mix

The nominal mixed concrete is generally used for small construction sites and small residential buildings where concrete consumption is not high. The nominal mixture provides the safety factor against various quality control problems that usually occur during the construction of concrete. Concrete mixture for construction is one for which mixing proportions are obtained from various laboratory tests. The use of structural concrete requires good quality control in the selection of materials, mixing, conveying and laying concrete. This concrete offers mixing ratios based on locally available material and offers economic viability in construction when executing large-scale concrete structures. Therefore, building concrete is used in large concrete construction projects. Therefore, a suitable grade of concrete can be selected according to structural requirements. Nominal mixtures for concrete grades such as M15, M20, M25 are generally used for small-scale construction work by different experiments. Large structures have high strength requirements and are therefore suitable for higher concrete types such as M30 and above. The mixing proportions of these concretes are based on the design of the mixture.

Building Mix.

Building Mix is suitable for manufacturing mortar for general laying of bricks and blocks. It can be used with all types of bricks and offers proven quality. Using the preparation stones and blocks should be wet before starting work. If they are too dry, the stones will absorb moisture from the mixture. This will weaken their strength. Mix the mixture in a wheelbarrow, plastic wrap or on a surface previously moistened with clean drinking water whenever possible. Empty the contents of the cement bag and mix thoroughly with sand and stone. Gradually add water and mix until you get a uniform consistency of the paste. Use a maximum of 7 to 8 liters of water. Too much water produces a weaker mortar. Do not try to work too hard by adding extra water when it is semi-dry. Curing To keep your project properly, avoid moisture by keeping it moist for 3 to 7 days. Gently spray with water and cover with plastic wrap, burlap or wet sand. 

Regular types of concrete and their uses

Regular types of concrete are M15, M20, M25, etc. For simple concrete work with cement, M15 is usually used. For the construction of reinforced concrete or concrete structure are suggested, at least the quality of concrete M20 is used. 

How to choose a suitable grade of concrete for construction 

The quality of concrete construction is selected based on structural design requirements. There are two types of concrete mix: nominal mix and construction mix. Nominal mixed concrete is generally used for small construction sites and small residential buildings where concrete consumption is not high. The nominal mixture provides the safety factor against various quality control problems that usually occur during concrete construction. The construction concrete mix is one for which mixing ratios are obtained from various laboratory tests. The use of structural concrete requires good quality control in the selection of materials, mixing, transporting and laying concrete. This concrete offers mixing ratios based on locally available materials and offers economic viability in construction when executing large-scale concrete structures. Therefore, construction concrete is used in large concrete construction projects. Therefore, a suitable grade of concrete can be selected on the basis of structural requirements. Nominal mixtures for concrete grades such as M15, M20, M25 are generally used for small-scale construction work. Large structures required high strength concrete and are therefore suitable for higher concrete types, such as M30 and above. The mixing ratios of these concretes are based on the design of the mixture. Regular types of concrete and their uses Regular types of concrete are M15, M20, M25, etc. For simple concrete concrete works, M15 is usually used. For the construction of reinforced concrete, at least M20 concrete grade is used. 

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

Choosing the right concrete grade for the construction job:

So what can these grades be used for and which is best for the job at hand? Below is a list of a few of the initial concrete grades and what they are best used for.

C10 grade concrete

C10 concrete is also known as generation 1 concrete and is designed with a strength of 10 Newtons/28 days. C10 is one of the most versatile concrete mixes and is used in many residential applications. Typical applications of C10 mixtures include ditch fillers, agricultural formations, general soil ligatures and drainage. C10 is not suitable for structural mass formations. 

C15 grade concrete

C15 is also known as Gen 2 concrete and is designed to have a strength of 15 Newtons/28 days. For anyone who wants to develop foundations for smaller walls or concrete steps, Generation 2 concrete is an excellent choice. Although the C15 is still not suitable for large industrial projects, it offers an excellent material for residential floors. 

C20 grade concrete 

C20 or Gen 3 concrete is designed for a strength of 20 Newtons/28 days. This mixture can be used to form lightweight bases and applications in residential projects. Typical applications of this type of concrete are the formation of interior slabs, driveways, garages and sheds. 

C25 grade concrete

C25 grade is by far one of the most versatile concrete mixes on the market. C25 is also called ST2 and can be used in many different residential and commercial building projects. These projects may include different concrete foundations, large-mass fillings, foundations and reinforced substrates. 

C30 grade concrete

Used for: Pathways and roadways (this is the lowest grade concrete mix that can be used for this purpose). More durable than the grades that have come before, and thus is much more weather-resistant and can take heavy road traffic. It is used in commercial structures

 C35 grade concrete

Used for: Commercial structures. This heavy concrete mix is usually used for creating external walls and slabs, as well as for structural piling. It is used bridge foundations or commercial structures

C40 grade concrete

Used for: Commercial construction sites, creating foundations and beams for structural support and roads. The most durable in this list, C40 can withstand chemical corrosion also, so is frequently used on farms where slurry could corrode structures or in septic tanks. It mostly use in commercial buildings