When it comes to the structural integrity of newly poured concrete, several different grades of strength can be used. The grades are chosen based on the components of the concrete mix being poured and the minimum expected strength (measured in newtons) of the concrete after 28 days of setting. Regardless of whether being used in residential or commercial applications, concrete grades were designed to help identify the most appropriate concrete mix for the job at hand.
Here is a list of the different concrete grades available and what they are best used for.
Standard Strength Concrete Grades
C10 Concrete Grade
C10 is also known as Gen 1 concrete and is designed with a 10 Newton/28 day strength. C10 is one of the most versatile concrete mixes and is used on many residential applications. Typical uses for C10 mixtures are in trench fills, agricultural formations, general floor binding, and drainage. C10 is not suitable for any structural mass formations.
C15 Concrete Grade
C15 is also known as Gen 2 concrete and is designed with a 15 Newton/28 day strength. For anyone wishing to develop foundations for smaller walls or concrete steps, Gen 2 concrete is an excellent choice. Though C15 is still not rated for large industrial projects, it provides excellent material for residential flooring.
C20 Concrete Grade
C20 or Gen 3 is rated at 20 Newton/28 day strength. This mixture can be used to form lightweight foundations and applications in residential projects. Typical uses for this grade of concrete are in the formation of internal floor slabs, driveways, garages, and sheds.
C25 Concrete Grade
C25 is by far one of the most versatile concrete mixes on the market. Also referred to as ST2, C25 can be used in many different residential and commercial building projects. These projects can include a variety of different concrete foundations, large mass fills, footings, and reinforced bases.
High-Performance Strength Concrete Grades
C30 Concrete Grade
One of the lower strength commercial grades is C30. Also known as ST3 or PAV1, C30 grade is mostly used during pavement construction. C30 is designed to withstand 30 Newton/28 day strength and is strong enough to use in reinforced bases, any outside paved area, or other lighter external applications.
C35 Concrete Grade
C35 or PAV2 is designed to withstand 35 Newton/28 day strength. Offering more substantial strength than C30 grade, C35 can be used on larger commercial buildings and foundations for added support. C35 also has special additives to reduce the likeliness of air bubbles forming, protecting against surface cracks from freezing temperatures.
C40 Concrete Grade
C40 is an extremely strong commercial-grade concrete with 40 Newton/28 day strength. C40 is the ideal choice in the construction of large industrial support beams and foundations. It is also used in a variety of roadwork applications and agricultural yards.
When using concrete in any construction project, it’s important to know which particular grade will best suit your application. By better understanding the concrete grade system, you’ll be able to make the right choice for the job at hand and ensure you have a strong finished product that will last.
Family owned and operated since 1969, Knight’s Companies is a concrete company in Columbia, SC. Knight’s upholds the highest standards in all aspects of the business, and will complete commercial concrete jobs other companies won’t even quote.