Nondestructive Testing for Concrete – What Is It and Why Do We Use It?

What Is Nondestructive Concrete Testing?  

Nondestructive concrete testing, also referred to as NDT, is testing that does not harm the structural integrity or structural strength of the concrete slab or structure. Nondestructive testing is used to determine the repair needs for a concrete structure or slab and to determine the kind of repair that would benefit the structure or slab the best.  

Why Use Nondestructive Concrete Testing?  

Nondestructive concrete testing is used when the concrete structure or slab needs to be assessed for repairs but still needs to be utilized. Nondestructive testing for concrete is ideal as it does not require the structure or slab to be closed for significant periods of time. Another reason NDT (Nondestructive Testing) is favored is because you can test multiple properties of the concrete, such as compressive, flexural and tensile strengths. 

What are some examples of destructive testing?  

Destructive testing includes mechanical testing (bending, impact tests, tensile) and macro / microhardness testing, as well as metallographic examination. Mechanical testing often requires a larger sample to be taken of the concrete from various testing areas, which can become costly and damaging to the structure. Some other testing requires active demolition of the structure to obtain samples and results. 

What are the disadvantages of destructive testing?  

Destructive testing has many disadvantages. First, traditional destructive testing cannot identify internal defects of concrete, such as bubble pores or corroding rebar. Another disadvantage of destructive testing is that specimens obtained from the larger concrete structure cannot be utilized or reinserted after testing. This means that there will be permanent changes to your concrete structure should you chose to utilize some methods of destructive testing. Destructive testing also does not detect early age deformities in concrete. Lastly, destructive testing makes achieving results that reflect the health of the entire structure difficult, as samples can only be taken from so many areas. Because of this, many destructive testing methods must be paired with other testing methods to obtain a holistic diagnosis of the concrete health and repair needs.  

What Is Pull Off Testing and Why Do We Use It?  

At Surtreat Solutions, one of our most relied on tests is the Pull-Off Test, or simply Pull Test. The pull test is used to measure the direct tensile strength of the concrete structure. To complete this test, a very shallow core is drilled perpendicular to the surface that is being testing. Then, a metal disc that matches the size of the core is applied to bonded to the surface using epoxy or a similar material. Once the adhesive material is cured, the metal disc is pulled until the surface fails. The load is then recorded as the maximum load that area can withstand.  

Why do people test concrete? 

Nondestructive testing is used to test concrete for a multitude of properties. The main result that is used to determine repair eligibility is tensile strength, which demonstrates the failure load of the structure. This can determine what kind of repair is needed and where the repair would be applied / administered. For Surtreat Solutions, we pride ourselves on testing every step of the way to ensure our solution is achieving the best results for your structure. We require our team of certified applicators to test your structure at multiple stages of the application process, including before, directly after application, and after the concrete has had time to fully absorb the solution.