Ground Penetrating Radar (GPR) is an ideal technique for performing pavement surveys of roads and runways to detect layer interfaces, changes in construction and highlight areas for further, intrusive investigation methods. GPR is also able to provide an indication of increased moisture content, identify wet areas, and detect other features such as voids and delamination.
GPR is entirely non-destructive (NDT) technology, which can be deployed from a vehicle operating at traffic speeds, without the requirement for road closures or traffic management.
How a pavement survey (pavement layer thickness analysis) is performed?
Most pavement surveys are performed using our dedicated vehicle mounted pavement GPR system. We attend site and undertake one or more GPR scans along each lane of interest, these scans are performed at traffic speeds and can operate up to 70mph, although lower speeds are preferred. The survey will normally be conducted at off peak times, but there is no need to organise traffic management or a road closure.
All the GPR data is saved for post processing and interpretation back in the office: for pavement surveys, no results are available on site.
We can add or remove additional GPR antennas to meet different requirements, and when necessary our GPR can interface with both GPS and a video camera, both of which aid in the accurate positioning of the GPR data in the post processing phase after the survey. We have a selection of GPR available and can customise solutions for specific requirements.
In the office, we import the GPR data collected on site into our dedicated GPR post processing software which allows us to visualise the GPR scans, interpret the data to identify the layers, and export the results. We are able to export position information into CAD format, and provide layering profiles in both report and Excel formats.
Small scale pavement surveys
When pavement surveys are requested for small areas, it can be useful to adopt a different methodology utilising hand operated equipment at walking speed. Although we lose the benefits of high speed and minimal local impact, we benefit from a much wider set of options in terms of equipment and how it is deployed. At lower speeds, data quality is also improved.
Why use GPR for pavement surveys?
Other pavement survey methods such as FWD (Falling Weight Deflectometer) and core samples, are static tests which are slow to perform and require road closures, whilst very useful, the data recovered is only relevant for the precise locations in which the measurements were taken.
GPR has the benefit of being continuous and mobile, allowing a much denser sampling of information which can be used to fill in the gaps between cores and FWD measurements, and to highlight anomalous zones to focus the other investigations.
A well planned survey will use GPR to complement the coring and FWD data.
GPR is not able to replace coring to determine asphalt density.
If you require a GPR Pavement Survey, contact KB GPR Surveys for a quotation at firstname.lastname@example.org