Non-Destructive Testing [NDT] techniques used within or over concrete are less standardized than equivalent tests for Metal Substrates. Guidelines may differ between manufacturers, specifications and supplier details, limiting the effectiveness of NDT techniques for evaluation of concrete structures.
Coatings over concrete have similar requirements for surface preparation and coating application as coatings over steel, but the NDT and inspection equipment used for quality control are not as well understood for this application. Dry Film Thickness measurements over steel are heavily standardized within Australia, with AS 3894 offering guidance for their use on site and AS 1580.108 and AS 2331 being more general and lab focused respectively.
This paper will present a recommended practice, taking into consideration manufacturer, applicator and coating supplier recommendations for thickness measurement, along with existing standards for testing of coating thickness over steel. It will discuss Ultrasonic Pulse Echo (UPE) based tests for coating thickness and how they compare to destructive measurements. It will also consider limits and benefits of the UPE measurement technique.