Pull Off Testing – What Is Pull Off Testing? How Is Pull Off Testing Used?

What is a pull test? 

Pull off testing is used to measure the tensile and compressive strength of your concrete structure. The materials and tools needed for a pull off test are a metal test disc or “puck”, epoxy and a pull off tester. To complete a pull test, first, the surface is prepped to ensure there are no debris between the disk and the substrate. Then, epoxy is used to attach a metal disc to the substrate. Once the epoxy is fully cured and the disc is bonded to the surface, the actual pull test can be completed using the pull off tester. The metal disc is pulled until failure occurs, which then is recorded as the maximum pressure the structure can withstand at that specific point.  

How are the results used?  

Pull off test results are typically used to confirm the bonding strength of the substrate of the structure to determine the adequacy of coating/overlay adhesion of the concrete as well as its point of failure, that will tell us if the substrate is ready to receive any coat or overlay, if not a Surtreat Solution can increase the compressive strength of concrete thus increasing the point of failure of the pull off test. For Surtreat Solutions, we use the results to prove the effectiveness of our solutions. Typically, we will perform several pull tests on the designated structure, including one before the application of our product and after our product has penetrated and treated the structure.  

How are results measured?  

Concrete strength is determined by measuring the force in kilo Newton’s (kN) needed to pull a 2 x 1 inch plug from the concrete surface. This force is also expressed in the more conventional psi compression strength scale. 

Some of our pull tests results:  

Surtreat Solution’s goal was inhibiting Formation of FOD Concrete Fragments. The concrete assembly ramps are 13 inches thick. Random fine cracks have developed as a result of the loading and unloading of C-17 aircraft taxiing across them over time. The cracks have enlarged, and additional small cracks have propagated from them. The SURTREAT® process involved the surface application of chemical formulations, which penetrate the surface to a minimum depth of 2 inches. From this, we acheived a a 62.6% increase in tensile strength of the concrete. 

 The increase in overall strength is incredibly significant in percentage terms and shows how SURTREAT® formulations can increase the surface strength of concrete. It is predicted that the increase may be even greater in areas along the crack faces, which have become weak and are prime sources of fragments and FOD (Foreign Object Debris). SURTREAT® inhibits the impact of FOD by increasing concrete strength.