Novel Approach to RAAC Plank Inspection with Proceq GP8800 GPR

A recent study published on Science Direct by Joshua B. Elliott, Darren Chaney, and Habib Murtaza [1] presents a groundbreaking approach to improving the inspection of RAAC planks, by utilizing a dielectric wedge in conjunction with the compact Proceq GP8800 GPR.

Reinforced Autoclaved Aerated Concrete (RAAC) has emerged as a significant concern in the construction industry, particularly in the UK. Used as a common construction material for public buildings like schools and hospitals between 1950 and 1980, the safety risks of RAAC are now being widely recognized. 

Non-destructive testing (NDT) methods, such as ground-penetrating radar (GPR), are ideal for assessing the condition of RAAC structures when the sensor can scan at an angle relative to the plank. However, with more complicated use cases, especially in areas obscured by supporting structures, it becomes challenging to interpret the results. 

The in-depth article shows how this innovative technique enables the detection and localization of critical features, including rebar and end bearings, even in previously inaccessible areas. 

Key Advantages of the Novel Method:

• Enhanced inspection capabilities: The GP8800 GPR and dielectric wedge make it possible to inspect areas of the RAAC plank that were previously obscured by the supporting beams. 
• Fast to deploy: With just one longitudinal scan towards the end bearing, it’s possible to obtain a suitable dataset to evaluate in-situ RAAC ceiling planks. 
• Reduced reliance on invasive techniques: The non-destructive nature of GPR, coupled with the enhanced capabilities of the new approach, minimizes the need for invasive inspections, reducing costs and potential damage to the structure. 

For a deeper dive into the technical details and experimental results, please refer to the original study. 

[1] Elliott, J.B., Darren Chaney, and Habib Murtaza, et al. (2024). Construction and Building Materials, 449, 138528.