August 20th 2020
A Guide to Different Concrete Strength Grades and When to Use Them
The strength of concrete influences how much of a load a structure can take. Certain types of buildings or surfaces will require a more durable concrete mix than others. The measure of concrete strength is done in a system of grades.
Different grades of concrete will have different strengths, and you can choose your grade depending on the nature of your project. The appropriate grade depends on the load the concrete will be taking, and have a typical range from grade C10 to grade C40.
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What grades are suitable for different types of concrete project?
The correct grade ensures there will be no weakening, which is what we call concrete fatigue. Concrete grades apply after a 28 day dry, which is how long is necessary for it to gain full strength. The formula for concrete grades uses various measurements.
Grading measures the compressive strength and tensile strength. Concrete has high compressive strength in comparison to other materials, meaning it can take a lot of weight. However, it is not the best in terms of tensile strength, meaning it does not have much flexibility to stretch or bend.
Compressive strength is the maximum weight concrete can take until failing, and you measure this in pound-force per square inch (psi). The tensile strength of concrete is the maximum stretching or pulling concrete can take, and you measure this in newton per square meter (N/m^2), kilogram per square centimetre (kg/cm^2) or psi.
Another measure of concrete strength is shear strength. A shear load is a weight that will usually cause sliding failure on concrete along the plane that is alongside to the alignment of the weight. Using beams can increase the shear strength of a structure.
Many people find it difficult to understand what grade of concrete is appropriate for a project. Each strength class has different applications. The following are some uses for different grades of concrete:
C10 concrete grade uses
You simply do not need to use a very strong cement for certain types of project. It would be unnecessary and costly to do so, and for some uses, it is desirable to use a weaker cement mix.
For smaller domestic or commercial projects, such as when laying a garden a pathway or when using patio slabs a weaker mix is perfectly adequate as the load that will be on the concrete is relatively low.
This particular grade of concrete is relatively useful for many types of small projects and is suitable for projects that you might have to replace in a few years. It is not suitable for structural work.
C20 concrete grade uses
This grade of concrete is more robust and can be useful for bigger commercial or residential projects. It is still a relatively weak mix in comparison to some of the grades of concrete available, which have a much higher strength.
Indoor flooring projects are one of the things it is useful for, so long as the structure of the building is one that is not too heavy. It is beneficial to use this grade for lighter structures, such as garages or sheds.
The types of floors this grade is suitable for includes floors in garages or workshops. Another potential use is for a driveway, but it is not a grade that is suitable for heavy use by vehicles.
C25 concrete grade uses
Ordinarily a concrete project will be undertaken using the appropriate concrete grade to save on costs, but also to make sure that any structural features are capable of standing on it safely.
This grade of concrete is a safe mix for use in foundations, which means it is strong enough to use for more substantial or more weighty structures. Foundations ensure that the structure will have adequate support.
It is a good choice for a range of general construction projects as it provides a large level of strength, but C25 is also not a grade that is so strong that it will offer an unnecessary amount of support.
C30 concrete grade uses
By this grade we are now getting into the territory of concrete that is particularly strong and suitable for a range of hard-wearing situations or larger scale projects.
As C30 is so strong, it is useful for roadways that will see a lot of traffic in their daily use by vehicles. It is also appropriate for pathways that will experience particularly heavy footfall.
This grade of concrete will tend to have a use in more commercial projects, and not be so useful for domestic projects. A key reason this grade is useful for commercial settings is the fact that it will resist weather more effectively.
C35 concrete grade uses
C35 is another example of a much more durable concrete that is useful in many commercial settings. The strength of this particular grade means it can be an appropriate choice for many types of structural work in a building.
This grade is useful for other areas in a commercial building too. The strength of the concrete here is such that it can withstand plenty of pressure and wears very well, which means it can be suitable for exterior walls.
When building taller structures adequate foundations must be present. Some larger buildings require deeper and more extensive pilings to support their weight, and C35 is useful for this aspect of construction too.
C40 concrete grade uses
Now we reach this grade, we are looking at the most durable concrete with a high level of strength. As a result, it is usually only suitable for much bigger concrete projects such as commercial buildings.
It is essential to use such a strong grade of concrete for the foundations of commercial buildings, particularly if they have multiple floors and will, therefore, carry a large load.
This concrete is also very resistant to chemicals, and will not corrode easily. This quality makes C40 useful for projects where there is likely to be strong chemicals in use, such as sanitation. A septic tank will commonly use C40.
Choosing concrete and grades for your project
Sometimes deciding what grade of concrete to use is difficult, but we can choose the appropriate one for many types of project. Appropriate grading is important to ensure that a structure is safe.
As there may be different parts of a project that use different grades of concrete, it is essential to choose accurately to make sure that each grade is suitable for each section.
Concrete strength expertise for a successful project
With a lot of commercial and residential proficiency, our services are capable of being versatile and commit to a high-quality outcome in an array of settings. This part of our approach leaves us with many satisfied clients.
We are pleased to guide you through some of the crucial things to know about concrete strength and grading. Now that you are ready to get your project underway, make sure you contact us today for an estimate.