Phaze Concrete explains various methods for testing the strength of concrete on-site.

Whether its new construction or old, evaluating the strength of concrete can be a challenging process. For existing structures, Phaze Concrete experts recommend non-destructive and non-intrusive methods to avoid unnecessary damage. Plus, there are other perks like saving money and reducing the amount of closure time. 

According to Phaze Concrete, strength is the most essential component for building and design codes. It must be measured to assess the durability and performance of concrete long-term to ensure the safety and integrity of structures. In this article, Phaze Concrete lists a few of the most commonly used on-site strength tests for existing structures. 

1. Compression Test

The compression test is one of the most popular methods due to being reliable and cost-effective. Phaze Concrete experts explain that the core surface needs to be prepped and cut before being tested. However, this method can be destructive and is not recommended for older structures that are more at risk for damages. The cut areas need to be repaired after samples are taken which can affect the overall integrity of the structure. 

2. Pull-Out Test

This method is typically used for testing the strength of structures that are new or in-progress of being built. To conduct a pull-out test, Phaze Concrete explains that companies will attach a piece of equipment to an exterior fixture like a bolt, nut, or screw. Then, workers will pull to bring the structure to its stress load level. Overall, the pull-out test method is easy and provides great insight into how strong the concrete is. However, owners can expect concrete to have damaged or crushed areas. 

3. Rebound Hammer

Phaze Concrete experts explain that the rebound hammer method works by measuring the rebound of a spring driver hammer mass after its impact with concrete. It is the most commonly used non-destructive method for field applications and helps to determine the uniformity of concrete.  Phaze Concrete notes that professionals must be on the lookout for subsurface voids which affect the test results. 

4. Ultrasonic Pulse Velocity

This technology measures how long it takes for ultrasonic waves to travel through the test area. Research has shown a correlation between the strength of concrete and the speed of waves. Concrete experts explain that ultrasonic pulse velocity is a great tool to use during quality control on materials to find damages in the structural components. It works not only with concrete but also with metals and welded connections. 

Just like the other methods mentioned previously, ultrasonic wave technology has its cons too. Rebar, voids, and cracks can impact the test results, which means that workers must be very specific and concise when it comes to finding test areas. 

5. Combined NDT

Finally, the combined NDT method uses a combination of tests to build more accurate final results. Phaze Concrete notes that this comprehensive strategy is most likely to produce the best comprehensive analysis.