Post-installed Rebar - Product Qualification [Part 1]

Post-Installed Rebar - Product Qualification [Part 1]

Why Product Qualification is arranged as the final topic in webinar series?

Throughout our webinar series on Post-installed rebar, we discussed on design codes, installation steps, inspection procedures etc. Some may wonder why we are putting product qualification as the last topic of our series. The major reason is because after listening to our webinars on the topic of design, installation and inspection, our audience will have a better understanding of the importance of product qualification and its relationship with many different stages of a Post-installed rear (PIR) installation.

Adhesion system used in PIR application

Generally, there are three main types of adhesion system in PIR application. The first is polymer adhesive, such as RE500V3 and HY200-R from HILTI, and they come with qualification standard. While the second one is cementitious grout, which is formed when workers mix cement and water in jobsite. This type of grout does not have product qualification and its performance is not consistent. The three type is hybrid grouts which is a combination of polymer & cementitious grout.

What could be the consequences while choosing the wrong adhesive?

Using the wrong adhesive can lead severe consequences. The first is project delay due to re-do & re-test on anchors. As specified, extra number of anchors have to be tested if there is pull out test failure. Secondly, poor installation quality will compromise the performance of the rebar. Compromised rebar performance will lead to health and safety concerns, such as the loss in lives & properties and lawsuit & repair cost in some severe cases. 

Code development in the past 20 years

There were many changes in the product qualification and design standard in the past 20 years. From Technical Report (TR) 023 to the latest replacement EAD330087, there are a few changes in the scope of the report and some factors are considered. 

What does TR023 talk about?

TR023 acting as the assessment method for PIR connection, it states the list of tests that must be carried out, such as low & high strength concrete test, test on installation safety, sustain load, installation direction and injection etc. Here comes a key question: What are the common features between them and why are we carrying out these tests? It can be observed that the variables in these tests are mostly related to site and installation condition.

Assessment criteria for tests

If we further investigate the assessment criteria of the tests, the criterion is measuring the deviation under different condition. The test is pass if the reduction in the compromised bond stress is less than 10%. Therefore, the aim of the assessment is to ensure the reduction of bond performance due to environment condition and human error is under control. 

Low & High Strength concrete test

The first test is the low & high strength concrete test. It tests the bond strength of the mortar across different concrete strength. It is important to note that only if the tested result in C20/25 and C50/60 are fulfilled, the design value of ultimate bond resistance according to EC2 can be used. 

[To be continued...]