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Hollow Core Concrete slap being lowered into place by a crane

When a concrete structure is designed, it’s very important that the concrete is tested for various properties. This is to make sure that it will be safe and that it can withstand a certain amount of wear. One of the most important properties to be measured is the compressive strength of concrete; the other is the tensile strength of concrete.

So, what exactly is the tensile strength of concrete?

Due to the brittle nature of concrete structures, they are highly prone to tensile cracking when different effects and loads are applied to them. This is why it’s so important to check the tensile strength of concrete. When engineers are testing tensile strength they are assessing the ability of the concrete to withstand cracking when it is pulled apart. In general, you will find the tensile strength to be a lot lower than its compressive strength.

How Is Tensile Strength Measured?

Tensile strength is measured in units of force per cross-sectional area (N/ or Mpa). Testing for tensile strength can be difficult due to the material’s tendency to break or crack, and this is why tensile strength is usually measured via indirect methods rather than a direct method known as a uniaxial tensile test. There are two indirect methods that are commonly used. These are a ‘Split cylinder test’ and ‘Flexural test’. These names all sound very technical so let’s break down what each of these tests involves a little more.

Split Cylinder Test

For this method, a compression testing machine is used. A diametral compressive load is applied along the length of a cylindrical concrete sample. The load induces tensile stress on the sample which is tested until it fails.

Flexural Test

This is another common method for testing the tensile strength of concrete and uses a flexural or ‘bend test’ machine as it is sometimes referred to. A concrete specimen is placed horizontally across two points of contact (lower support span of the machine) before a force is applied to the top of the specimen. The force is applied via the upper loading span and the test is in the process until the sample fails.

What Can Be Done To Improve The Tensile Strength Of Concrete?

As we’ve mentioned, although concrete is high in compressive strength it is low in tensile strength. This is because the material is naturally brittle and the result of combining a number of different aggregates. Luckily, it is possible for the tensile strength of concrete to be improved by prestressing it. Prestressed concrete is more resistant to the impact of stress which makes it less likely to crack and wear when a load is applied.

Al Manaratain leading the way…

Aware of the benefits that prestressed concrete can have on improving the tensile strength of concrete, Al Manaratain has developed reliable prestressed concrete products of our own. If you would like further information on any of our prestressed concrete products, please do not hesitate to get in touch with us today where a member of our skilled team will be more than happy to help.