Non-destructive material evaluation of a reinforced concrete viaduct: a practical methodology

The use of non-destructive tests for assessing the material status of concrete structures in the Netherlands remains relatively uncommon, despite the growing demand for the preservation of existing structures under the VenR policy of Rijkswaterstaat. Skepticism towards NDTs is reflected in the scarcity of documented case studies in publicly...

GPR wavefield phenomena in the presence of boreholes and permittivity gradients

Ground penetrating radar (GPR) data has proven to be a powerful tool for non-invasively estimating the electrical properties of the shallow subsurface. Petrophysical relationships allow them to be converted into hydrological parameters such as soil water content (SWC) and porosity. In the presence of thin layers, complex wave phenomena can occur...

Time-lapse GPR full-waveform inversion to monitor heat tracers at the Krauthausen test site

Understanding solute and heat transport processes in aquifers is crucial for monitoring and protecting the groundwater critical zone. Crosshole ground-penetrating radar (GPR) is a useful method for enhancing transport characterization in aquifers. Particularly, GPR full-waveform inversion (FWI) can provide subsurface images with resolution at...

Image data filtering and automatic detection of damages within asphalt with the help of ground-penetrating radar (GPR) and machine learning methods

Damages within asphalt have been interesting phenomena in asphalt engineering, the detection of which is significant for maintenance of road sections. This project focuses on cracks and delaminations. An attempt was made to filter radar image data with a method based on a VNA-antenna-multilayered system model as well as the data from two...

Measurements and numerical simulations of the effects of inclination and height of a GPR antenna above ground

Landmines and Improvised Explosive Devices (IEDs) are among the most dangerous weapons found in (former) conflict areas. Many of them have only minimal or even no metal built in making it difficult to detect such devices via conventional metal detectors. Thus, alternative methods such as Ground Penetrating Radar (GPR) are deployed for this...

Feature extraction of GPR data for the classification of reflectors in reinforced concrete

During their service live reinforced and prestressed concrete structures experience deterioration. Therefore, to effectively assure the safety and durability of the compounds, non destructive testing methods, such as Ground Penetrating Radar, employed at high frequencies, provide a rapid assessment of the geometry of the compound. Although...

Detection of cavities in levees caused by the muskrat and other mammals by use of geophysical methods

A wide range of wildlife has their habitat around and within levees or other types of embankment structures. In the Netherlands the burrowing of the muskrat causes internal and external erosion, altering the geometry of the earthen structure. As often century-old embankments protect the densely populated land against the water, the burrowing can...

Hoe presteren schoolgebouwen op levensduurkosten?

Dit onderzoek is opgezet om kennis bij te dragen aan achterliggende oorzaken van de suboptimalisatie op de levensduurkosten van voortgezet onderwijs scholen. De twee hoofdvragen van dit onderzoek zij als volgt geformuleerd; Waardoor worden kostenoverschrijdingen op de levensduurkosten veroorzaakt bij recent gebouwde voortgezet onderwijs scholen?...

Waarderen van duurzaamheid

Onderzoek naar het waarderen van duurzaam vastgoed met behulp van de instrumenten BREEAM-NL, GPR-gebouw en Greencalc met een focus op nieuwbouw utiliteitsbouw gebouwen. Het onderzoek laat zien hoe de instrumenten worden toegepast en hoe de duurzaamheidwaarderingen zich met elkaar verhouden.

UWB Air-Coupled Antenna for Ground Penetrating Radar

Ground Penetrating Radar (GPR) is a promising technology to detect buried objects beneath or near ground surface. To achieve high-resolution and accurate enough images, the transmitting antenna (TX) in this technology is required to radiate a highly-correlated narrow width pulse towards ground where the targets are hidden. For this application,...

GPR Antennas Design and Experimental Evaluation

This Thesis covers the expermimental evaluation of a resistively-loaded bow-tie antenna for the purpose of utility detection with GPR. Numerical analysis has been carried out with a designed resistively-loaded printed dipole antenna to gain a better understanding of the subsurface scattering phenomena, loading effects of the ground and other...

Imaging frozen glacio-fluvial bedrock valley infill using Ground Penetrating Radar

A Ground Penetrating Radar (GPR) survey was conducted in April of 2008, collecting 27 km of radar profiles in Sandflugtdalen, a permafrosted glacio-fluvial bedrock valley in West Greenland. Due to low electric permittivity of frozen soil, GPR has good depth penetration of permafrost, up to 80 m using low-frequency (50 MHz) antennae. Resolution...

A texture analysis of 3D GPR images

In this thesis, image processing algorithms are applied to 3D GPR images, in order to improve the detection capabilities of a radar system. Detection based on the magnitude of the reflected signals may miss weak targets. On the other hand, an analysis of the texture properties of a target, i.e. the repeating pattern all over the surface, which...