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Non-Destructive Concrete Testing Methods

Non-Destructive Concrete Testing Methods

Non-destructive concrete tests are performed to ascertain the comprehensive strength of concrete as well as other properties from the existing structures. 

The standard method of evaluating the quality of concrete involves testing specimens for flexural, compressive and tensile strengths. 

There’s a disadvantage here because the tests are not obtained immediately. 

Some of the non-destructive concrete tests include penetration, rebound hammer, pull-out test, ultrasonic pulse velocity and radioactive methods. 

1. Penetration Concrete Tests 

Some of the equipment used for this test include: 

  • Powder-actuated driver or gun
  • Hardened alloy probes 
  • Loaded cartridges 
  • Depth gauge (used for measuring the penetration effect of the probes and other equipment)

The probe is driven into the concrete using a precision powder charge. The depth provides a clear indication of the concrete’s compressive strength. 

This test provides variable results and might not be used to get accurate values of the strength of the concrete. 

One main benefit is that only minor patching is required on the exposed holes. 

2. Rebound Hammer Method 

It’s used to test the surface hardness of the concrete. Here, the Schmidt hammer is used where it is forced against the concrete surface. 

The test can be performed vertically or horizontally but proper calibration is essential. 

It’s a good method for testing concrete strength but accuracy is determined by the concrete specimens that have been tested and cured under the right conditions. 

The accuracy might be affected by the texture of the surface, shape, size, moisture, type of cement and much more. 

3. Pull-Out Concrete Tests

This test is used to measure the special ram of the concrete. This is the force required to pull a customised steel rod from the concrete at about 7.6cm deep. 

The concrete might be in tension as well as shear but the needed force to pull the concrete depends on the compressive strength. 

The pull-out concrete test can also be used to measure the in-situ strength of the concrete quantitatively with the proper correlations in place. 

The test doesn’t measure the interior strength of the concrete but it can be used to assess the maturity and development of any concrete specimen. 

These tests are beneficial in measuring the strength of the concrete quantitatively. 

It’s a non-destructive test but if the pull-out force is minimum the results are ineffective. 

4. Dynamic Non-Destructive Test 

Currently, only this method can be used to determine the potential strength of concrete in-situ. 

It’s used to determine the length of time required for the pulse to move through the concrete. 

The tests can be done with small concrete specimens or entire concrete structures. 

There are a few factors that affect the measurement. These include the following: 

  • There must be a smooth contact with the concrete surface during testing. 

That’s why using a coupling medium like a thin film oil is necessary for this step. 

  • To prevent any errors caused by heterogeneity, the path lengths need to be at least 12 inches.
  • The pulse velocities are not dependent on the temperature but you should recognise that the pulse velocity increases because of the freezing water temperatures. 
  • Reinforcing steel in concrete creates an appreciable effect on the pulse velocity. 

Therefore, it’s ideal to choose the best paths for the pulse velocity that would not influence steel reinforcements. 

That way, you can make the necessary corrections if the steel is found in the pulse path. 

It’s a good test to determine whether the concrete is uniform. It can be used on structures under construction or those already established. 

If there are huge differences in the pulse velocity, it’s prudent to presume that the concrete might be deteriorated or defective. 

If there are high pulse velocity readings, it’s a sign of good quality concrete.

If you have any construction or excavation projects on the go, it is vitally important to hire a concrete scanning company to scan the location first. 

High Resolution Concrete Scanning is a company you can trust to provide you with the most accurate and detailed information when it comes to scanning your concrete structures. 

They have years of experience and use the most advanced tools and equipment in the business.

At High Resolution Concrete Scanning, our specialisation in concrete scanning services has made us industry leaders. If you need to perform any type of concrete scanning, then look no further than us at High Resolution Concrete Scanning.

Please call us today on 0437 365 830 or contact us through our website www.high-res.com.au/contact-us/

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