Estimating material properties of natural materials is a goal shared between near-surface exploration, infrastructure management, and even conservation of historic sites. Existing methods (e.g., seismic, ultrasonics, and direct testing) for characterizing these properties of interest are not yet available at the desired scale or configuration. GPR is an established method for characterizing the physical configuration of these sites by mapping subsurface features. A new analysis method applying seismic and image processing attribute analysis to GPR data has promising results for material identification and possibly characterization. To further explore this capacity, an experiment to characterize concrete laboratory specimens using GPR was performed. Creating a unique data set, GPR scans and attribute analyses are paired with direct testing of the samples. A variety of attributes and regression analyses have been able to predict porosity of the samples from the mean instantaneous GPR amplitudes with some success (R2 = 0.8). Density and compressive strength are more difficult to predict from the GPR data, but porosity is an excellent proxy property that can be related to other physical properties using secondary relationships. By continuing to explore these relationships and test them on GPR data for other materials (stone, brick, etc.), the results could be extended and refined to provide fine-scale estimation of important properties to characterize reservoirs, basins, and other geological or anthropogenic features of interest.

The conservation of historic cultural heritage sites is an endeavor that often brings together a diverse group of methods and interests. Castelul Corvinilor, also called Corvin’s Castle or Hunedoara Castle, in central Transylvania (Hunedoara county, Romania) is no exception. The first stone fortification of the medieval castle can be dated to the 14th century and has undergone significant expansion since the original structure was completed. The main building campaigns started in 1440 with the conversion of the fortress into a castle, followed by two more major campaigns during the 17th and 19th centuries, including restoration and remodeling of the original areas. The castle’s historical significance and touristic value make conservation an important goal for the site. This area has been the subject of limited and opportunistic (salvage) archaeological investigations, hoping to understand earlier phases of an administrative complex in the courtyard. However, the excavations did not establish a complete stratigraphy. A ground penetrating radar survey over most of the courtyard was conducted with a 500 MHz antenna, including the main courtyard area. This GPR survey of the courtyard was able to confirm some results of the archaeological excavation and located additional structures which were previously unknown. This presentation included analysis and interpretation of the data in both radargrams and depth slices. They reveal further horizons which indicate bedrock and possible reflections from structures dating to even earlier phases of the site.