what-concrete-slump-do-you-need

All about Concrete Testing …

Concrete is a composite material made of cement and aggregates (like sand and gravel) held together by water. The strength and quality of the concrete are determined by the ratios used when combining the components.

Because concrete is an essential component of the construction process, it must be subjected to quality testing to establish its state.

What is Concrete Testing?

Concrete testing might not be familiar or even seem like a hassle for a smaller home concrete contractor. But when issues or queries with projects surface, the testing process’ comparatively low cost soon compensates for itself.

A contractor is better equipped to handle any issues that arise, such as poor strength or cracking, if they assess the qualities of fresh concrete during placement.

Concrete testing is conducted as part of the quality control of concrete structures. Several quality tests on concrete, including compressive strength tests, slump tests, permeability tests, etc., are utilised to ensure the quality of the concrete supplied for a particular specification. These concrete quality tests provide insight into the material’s strengths, durability, air content, permeability, and other characteristics.

What are the Types of Concrete Testing?

Several concrete tests are needed based on whether the concrete is hardened. Here are the necessary concrete tests that must be carried out:

  • Compressive Strength Test

Compression testing is a type of laboratory test used to determine the strength and durability of concrete.

Approximately 150mm x 150mm x 15mm cubic moulds are used to measure a sample batch of concrete (or 100mm x100mm x100mm). A minimum of three cubes are usually obtained from each sample and stored at specific temperatures depending on when the cube is to be analysed.

If the cube is scheduled to be tested for more than seven days, it should be stored between 15 – 25 degrees Celsius; if it is expected to be tested for fewer than seven days, it should be held at 18 – 22 degrees Celsius.

The concrete sample is then placed in a compression testing machine, which applies a prescribed amount of force to the concrete to determine the extent to which it cracks.

  • Slump Test

The consistency of the concrete affects how well it will pour, handle, and compact. The term slump refers to the measurement used to determine the consistency of concrete. Consolidation and mortar loss issues can arise if your slump is too low (runny) or too high (thick).

To do the slump test, take a sample of your freshly mixed concrete and pack it into a cone with the following dimensions: 2 inches high, 8 inches wide at the bottom, and 4 inches wide at the top, all of which must be open. Lift the concrete at the cone’s top rim to level it, leaving the cone’s base unsupported.

The difference between the top of the cone and the level at which the concrete settles in your slump. To determine if your concrete has a good consistency, compare this figure to the slump value on the package in which your concrete mixture arrived.

concrete-slump-test

  • Air Content Test

Concrete’s air content impacts how well it will perform when frozen by cold weather and subsequently thawed by warmer weather.

Because air is lost during shipping, consolidation, installation, and finishing, the air content test only provides information on the amount of air in freshly mixed concrete. This test can be performed using one of three different devices.

The Pressure Type B Meter applies pressure to a sample of concrete to condense the entrained air; the change in the air is then used to calculate the air content of the concrete.

You can also use a Volumetric Air Meter. This machine removes air from a specific volume of concrete. To determine air content, compare the new volume of the sample to the rest of your concrete.

Finally, you can use an Air Indicator Kit. Fill the given vial halfway with concrete and then with alcohol. The change in the alcohol level reveals the air content of the concrete.

  • Water Permeability Test

A water permeability test is performed to determine the concrete’s durability and resistance to water under hydrostatic pressure.

This test is performed on concrete substructures such as foundations, concrete water tanks, retaining walls, etc.

  • Rapid Chloride Ion Penetration Test

The Rapid Chloride Ion Penetration Test, like the water permeability test, is used to test the durability of concrete. The test measures a concrete sample’s resistance to chloride ion penetration.

  • Unit Weight Test

A unit weight test is performed to determine the air content of a concrete mix and to ensure that the volume of concrete is within the approved project mix plan. It is critical to assist you in verifying that you have the requested volume of concrete.

Conclusion

Concrete testing helps to ascertain the integrity of a construction project and ensures that any risk of future harm caused by collapses is minimised. Before a building project, you must ensure that all required tests are duly conducted. Get in touch and we’ll do the concrete testing for you