Ground-penetrating Radar Studies Research Articles

Investigating the Internal Deterioration of the Auriga Statue of Mozia Island, Sicily, through Ultrasonic and Ground-Penetrating Radar Studies

The Greek marble statue of the Auriga of Mozia Island, in Sicily, is the most important artwork displayed at the Whitaker Foundation Archaeological Museum. It underwent geophysical investigations twice, in 2012 and 2021, to assess the marble’s degradation. The 2012 investigation prepared the statue for transfer to the Paul Getty Museum in New York and repositioning on an anti-seismic pedestal. The 2021 investigation evaluated potential new damage before another transfer. Both investigations utilized 3D ultrasonic tomography (UST) to detect degraded marble areas and ground-penetrating radar (GPR) to identify internal discontinuities, such as fractures or lesions, and locate metal pins that were previously inserted to reassemble the statue and its pedestal. Results from the UST indicate an average marble velocity of approximately 4700 m/s, suggesting good mechanical strength, with some areas showing lower velocities (~3000 m/s) within the material’s variability range. The GPR profiles demonstrated internal signal homogeneity, excluding internal fracture surfaces or lesions, and confirmed the presence of metallic pins. This study highlights the effectiveness of integrating UST and GPR for non-invasive diagnostics of marble sculptures, providing detailed insights into the marble’s condition and identifying hidden defects or damage.

Studying the Structure of the Road Pavement and Specifying the Repair Method

Studying the structural condition of road pavement is essential for making effective decisions about the type of maintenance or rehabilitation that will be carried out on a pavement section. Reliable quantitative assessment of the volume of necessary repairs will ensure the performance characteristics and durability throughout the entire service life at minimal cost. This article presents detailed results from Falling Weight Deflectometer (FWD) and Ground Penetrating Radar (GPR) studies. In addition, an analysis of these results and recommendations for strengthening the road pavement for the Sh-176 “Sighnaghi-Saint Nino Monastery” road to develop rehabilitation and maintenance scenarios. FWD results combined with road pavement layer thickness and traffic load information to determine residual service life and necessary treatment type. Thus, using the nonlinear theory of layered halfspace elasticity, pavement structure analyzed in the same way as other civil engineering structures.

Побудова твердотілої моделі історичного об’єкту: на прикладі форту «Марушка Ліс»

Purpose of this work is to use terrestrial laser scanning for analysis and construction of a digital model of the fort “Marushka Lis” focusing on the process of data collection, processing, and their further use, particularly for web mapping of post-military sites. In the modern world, the preservation and restoration of historical structures is an important task that requires the application of advanced technologies. Methodology. Terrestrial laser scanning serves as an indispensable tool in this process, providing accurate and detailed spatial data. A technological scheme for creating a digital model of a historical object has been proposed. The study of historical objects using various methods of information collection was considered, namely: topographic surveying, terrestrial digital photogrammetry, terrestrial laser scanning, ground-penetrating radar studies, tachymetric surveying, GNSS. The methodology for creating a digital model of a historical object and the presented technological scheme, which includes data collection, processing of the obtained results, and output data, are described. Results. A comprehensive approach was applied to create the model, which included studying the history of the object, terrestrial laser scanning, terrestrial digital photogrammetry, and conducting geodetic measurements. A key aspect was the accurate and detailed reproduction of all architectural and structural elements of the fort. The use of software such as Leica Cyclone REGISTER 360, Autodesk ReCap, and Autodesk Revit allowed the integration of collected data into one accurate and detailed model. The sequential execution of work according to the proposed methodology enabled the creation of a digital model of the fort “Marushka Lis.” Scientific novelty and practical significance. The scientific novelty lies in the use of terrestrial laser scanning and 3D modeling for the reconstruction of a destroyed post-military object. The obtained digital model of the fort “Marushka Lis” will be used in web mapping of post-military sites in Lviv region.

Ground Penetrating Radar Survey of Arctic Polygonal Wedge Structures

Ground Penetrating Radar Survey of Arctic Polygonal Wedge Structures

Improvements in Rock Mass Description for Stope Design by Geophysical and Geochemical Methods

Stope design is an important part of mine planning, and it aims to balance ore recovery, ore dilution, and production costs without compromising the safety aspects. This paper summarizes the main results from the research, which aims to introduce new techniques to describe the ore body and surrounding rock mass at the tunnel face prior to stope excavation. The research comprises a literature review and a survey among mining professionals to assess current stope design practices. The study identifies geotechnical data, software improvements, and integration of design into mine planning as the most critical areas for improvement. The empirical part of the study proposes new techniques for fast data acquisition. The laser-induced breakdown spectrometry (LIBS) technique is developed for measurements at the tunnel face and from core boxes to provide mineralogical and geometallurgical data. Ground-penetrating radar (GPR) studies are conducted to improve discontinuity characterization, and rapid photogrammetric methods are proposed for efficient tunnel geometry characterization. The techniques discussed in this paper already have many industrial applications. This study reveals their potential to be adopted and further developed to serve ore and rock mass characterization for stope design.

Ground penetrating radar (GPR) analysis of the deformation in the submerged drainage route at Ashour Bridge, El Bahira governorate, Egypt

ABSTRACT An underground structure called a siphon allows irrigation of water canals and channels to pass underneath water drains. Three groups of loads that may have an impact on the siphon’s Geotechnical stability are: (1) loads brought about by traffic and truck duties on bridges; (2) loads brought about by drain water on the siphon’s body; and (3) loads brought about by irrigation channels and the dynamic movement of sandals and bots. To address the problem, surveying was done to see if the body of the submerged Syphon had any deformations. A ground penetrating radar study of the research area will be used to pinpoint the exact location of the damaged parts and the areas of deformation in the body of the submerged Syphon. On the southwesterly side (the exit), three GPR profiles were made, and on the northeastern side (the mouth), five. To display the covered drainage body’s infrastructure, the measured GPR data were processed differently. Deformities and distortion areas in the body of the submerged siphon were discovered at various places and depths on the two sides of the siphon after the processed data were analyzed.

Using Ground Penetrating Radar (GPR) for detecting a crypt beneath a paved church floor

After the discovery of an archive document regarding an underground crypt beneath the f loors of the Church of St. Margaret (Sv. Marjeta) in Dol pri Ljubljani, Slovenia, further research was carried out to confirm its presence. An area filled with construction waste was discovered during a recent small-scale renovation of the church floor. This finding suggested the potential underground chamber may have been partly filled in during one of the previous restorations. A non-invasive GPR study was carried out along eight profiles inside the church to prove the existence of an underground crypt. Results show the presence of an air-filled chamber, confirmed later by a hole drilled in the floor. Additional findings in the church archive and pictures taken by a camera, lowered through a drilled hole, revealed three previously unknown caskets in the crypt. According to the archives, two of them belong to Baron Wolf Daniel Erberg and his wife who died in 1783 and 1774, respectively.

ГЕОФІЗИКА ПЕДОСФЕРИ В КИЇВСЬКОМУ УНІВЕРСИТЕТІ

The development of studies of geophysics of pedosphere in Taras Shevchenko National University of Kyiv over the past thirty years is considered. The pedosphere is a unique and extremely informative object for the geophysical research. The physical and chemical properties of the objects within the pedosphere are related to the mineral deposits, soil science processes, anthropogenic influence during agricultural production, environmental pollution, paleogeographic processes, the history of human development as an archaeological heritage. In Ukraine, the study of soil magnetism began in the 90s of the 20th century in Kyiv University on the basis of the Student Design and Research Bureau. At the present moment, the investigation of all the initiated processes continues. The understanding of the physical foundations of the method is essential. The magnetic mineralogy of soils is investigated depending on the conditions of formation or introduction: pedogenesis, technogenesis, influence of hydrocarbons, etc. The new data at the same time verify the already existing theory, as well as deepen the not yet known aspects of the study of the pedosphere, raise new challenges to researchers. Analyzes are carried out both at the macro level within agricultural fields, urban agglomerations, oil and gas-bearing regions, and at the micro level for the smallest soil aggregates (pedon), magnetic minerals, magnetoactive domains, etc. The results of magnetic, magnetometric, electrometric and ground-penetrating radar studies in various spheres of the national economy are given.

Geophysical studies of permafrost conditions of the Kangalassky coal mine dam

Problem statement. Geophysical studies of the ground dam body and base at the Kangalassky coal mine were carried out as part of monitoring related to the dam’s destruction, propagation of flank release fractures parallel to the ledge, and water seepage into the open pit. The main function of the ground dam is to protect the mining site from the inflow of surface water and preserve frozen rocks of the geological base. The mine workings of the coal mine are watered due to precipitation in the summer, snow melting and frozen rock thawing in the spring. Research objective is to assess the permafrost-ground conditions of the site according to geophysical methods and establish the boundaries of seepage flows that seep through the body and base of the ground dam. Methods of research. Electrical sounding at the dam site were performed by the electrical resistivity tomography method. The research was carried out with the Omega-48 equipment. Ground Penetrating Radar (GPR) study was carried out with a georadar of the OKO-2 series (AB-250M, central frequency 250 MHz). Georeferencing for comparative analysis of GPR parameters and positioning was carried out by the Geobox Fora Smart high-precision (geodetic) GNSS receiver. The cryogenic condition of rock was determined from the drilling data and FLIR SC660 thermal imaging camera data (device by the Shared core facilities of the Federal Research Center “Yakutsk Science Center SB RAS”, grant no. 13.TsKP.21.0016). Results. The results of GPR studies by the method of multi-season measurements in spring and autumn made it possible to objectively assess open pit permafrost conditions that reflect rock mass condition features (frozen or thawed rocks) and the position of the weakness zones (seepage areas and the presence of waterlogged soils). The analysis of geoelectric sections has identified anomalous areas with reduced electrical resistivity interpreted as zones of suprapermafrost surface water penetration into the embankment body with further dam base soil erosion. Possible surface waters migration routes and frozen rock degradation areas have also been identified. Scope of results. The described technique can be used at the enterprises of the mining complex in the North of Russia for engineering-geological and geocryological monitoring of mining and engineering structures.

On the Development and Application of Airborne GPR Solutions

Recent development of ground penetrating radar (GPR) technology, together with effective unmanned aerial vehicles (UAVs), have made it possible to carry out airborne GPR measurements across areas otherwise difficult to access and survey. The interest in airborne GPR studies has therefore been rising steadily in recent years and applications are many, including bathymetry, glaciology, archaeology, near-surface geology, ice- and snow thickness, road planning, peat, and wetland studies. However, airborne GPR measurements introduce several challenges that affect surface-based measurements to a lesser extent. Some of these challenges are regulatory, others of a more technical nature. In this article, we will discuss the effects an airborne antenna solution has on antenna footprint, unwanted signal input and signal loss. We will also describe a few scenarios where airborne GPR has been successfully used. Throughout the included studies, and depending on the application, different MALÅ GeoDrone antennas (developed and manufactured by Guideline Geo) have been used. At this point, it is also important to remind the reader the importance of adhering to local and regional regulations regarding the use of both UAV and GPR equipment.

Mapping the near‐surface trace of the seismically active Kachchh Mainland Fault and its lateral extension in the blind zone, Western India

ABSTRACTThe W–WNW‐striking Kachchh Mainland Fault (KMF) is the largest intra‐basinal fault in the Kachchh Rift Basin (KRB) located at the western continental margin of the Indian plate, and is responsible for several historic earthquakes, including the 2001 Bhuj earthquake and the 1956 Anjar earthquake. The objective of the study is to constrain the precise location and near‐surface characteristics of the KMF using field and ground penetrating radar (GPR) studies. Efforts were also made to ascertain and map the eastward continuity of the KMF. The fault has a prominent geomorphic expression up to the east of Devisar, where the KMF scarp finally dies out. The KMF marks the lithotectonic contact between Mesozoic rocks in the south and Tertiary rocks in the north. The segmented nature of the KMF has been previously attributed to transverse faults, complex deformation zones and heterogeneous assemblages of unconformable Quaternary deposits. Eight survey sites between Nirona and Sikra were chosen for near‐surface investigation of KMF using GPR. Comparatively, high‐amplitude radar reflections were received from well‐compacted sand‐ and shale‐rich Mesozoic rocks, whereas low‐amplitude weak reflections were observed from softer and clay‐rich Tertiary rocks. In the upper section of the GPR profiles, Quaternary deposits display low‐ to moderate‐amplitude semi‐continuous to wavy reflections. The traceable length of the KMF has been extended eastward by ∼20 km through the current study, which is considered a blind zone as feeble surficial evidence is present, but the fault trace is confirmed near the surface using GPR. The eastern part of the KMF is inferred to be a near‐vertical north‐dipping normal fault based on GPR data analysis. The tendency of the KMF to transform into a reverse fault in the vicinity of the intersection with transverse faults implies zones of relatively higher stress accumulation that might activate and trigger devastating earthquakes in the future.

Ground Penetrating Radar (GPR) survey over a melting blue ice area (BIA) at the south of Schirmacher Oasis, Dronning Maud Land, East Antarctica

A blue ice area (BIA) is located in Dronning Maud Land, East Antarctica between Schiermacher Oasis (SO) and Ulthat mountain ranges. High-resolution ground-penetrating radar (GPR) survey has been carried out in the northern boundary of the BIA surrounded by Schirmacher Oasis (SO), Shivalinga and Veteheia nunataks to examine if the BIA in the area is wind-induced or melt-induced in nature. GPR study reveals that the glacier in this part of BIA is warm and showing prominent signatures of subsurface melting in the vicinity of the nunataks and other exposed rock masses. The signatures of bottom warming also have been detected in few profiles which are in agreement with the drilling results in nearby areas. Melting signatures vary over the area depending on the distances from the exposed rocks and proximity of subglacial bedrock topography. The results indicate the possible higher heat supply by the exposed rock mass to the BIA. Folding of the internal layers and the presence of two firn pockets also have been observed near the nunatak Veteheia. The present GPR study concludes that the survey area is predominantly melt-induced BIA. Further investigations are recommended to study the firn pockets and mass balance of the area.

GPR application for the characterization of sinkholes in Teresina, Brazil

The town of Teresina, in the state of Piauí, Brazil, presents a history of land sinking processes. Two sinking events deserve to be highlighted, the first occurred in 1999 at Simplício Mendes Street and the other occurred on July 31, 2008, at Francisco Mendes Street. To identify possible shallow caves and associated structures, the Geological Survey of Brazil/CPRM developed a Ground Penetrating Radar (GPR) study to verify the occurrence of reflection patterns characteristic of these dissolution structures. In the field, the team conducted GPR sections along streets with a history of collapse. The GPR results obtained with shielded antennas of 200 MHz allowed the identification of old areas of collapse of the terrain, to a maximum depth of 3 m. In addition, the results obtained by this study show the potential of applying the GPR method in the characterization of the subsoil of paved streets, making it possible to identify various layers: asphalt, actual pavement, subgrade pavement, soil, saprolite, and mixed material. The high clay content of the subsoil does not allow the GPR to investigate further depths in the research area. The interpretation of aero-magnetometric data shows that the occurrence of sinkholes is associated with magnetic lineaments mainly in the NW–SE direction and enhances the understanding of the structural framework of the study area.

Tectonic geomorphology along the transverse basement fault (Moradabad fault) in the Ganga basin: A nexus between the Himalayan tectonics and the pre-Himalayan transverse basement structure

The present study focuses on the neotectonic perspective of a subsurface basement fault, i.e., the Moradabad Fault (MF) in the Ganga basin. This is a ∼163 km long NE-SW trending prominent pre-Himalayan subsurface structure that participated in many phases of tectonic movement during and after the Himalayan orogeny. At present, it is deep-buried under the alluvium, and frequent geomorphic readjustments are seen in the fluvial archives around this fault. The datasets presented here include tectono-geomorphological analysis, transverse-tectonic analysis, previous seismic records from the earthquake catalogs and the associated seismites, and the Ground Penetrating Radar (GPR) studies. The available geological maps limit the northern end of the MF at the Himalayan front, and further northward, it is marked as lineaments. However, the recent geological evidence such as the river alignment, river confluence, landslides, faceted spurs, triangular facets, truncated spurs, fault scarps, structural terraces, and the alignment of the low to moderate magnitude seismic events having parallel trends with the MF may conclude that it is not just a matter of coincidence. However, these features are likely aligned due to the post-Himalayan reactivation-regeneration of the basement structures. It is, therefore, argued that these linear structures showing active deformation are the extension of the MF into the Himalayas, and hence the lineament terminology for these structures should be abolished. The MF has a curved fault-line with the existence of the releasing bend in a transtensional regime. The up-thrown block shows the signs of compression, evidenced by the geomorphological signatures. The fault-bend is characterized by oblique deformation may be accommodated by oblique-slip faulting or dip-slip fault displacements. Tectonic geomorphological characteristics, morphostratigraphic record, GPR data, seismic events, and the basement contour model suggest the Moradabad fault is neotectonically active and is influenced by the Himalayan tectonics.

Identification of River Ice Cover Structure by Ground Penetrating Radar Data

To predict and prevent emergencies resulting from dangerous ice phenomena (ice blocks, insufficient ice cover capacity, ice jams), information on the structure and thickness of river ice cover is required. Currently, the ground penetrating radar (GPR) method is used for operative research of ice cover condition on long river sections during the freeze-up period. The article presents materials of interpretation of the GPR studies of the ice cover structure of the Lena River in the vicinity of Yakutsk. Analysis of the parameters of radargram wave patterns (fragmentation, subhorizontal, broken, continuity of reflected wave events, amplitude and phase of reflected waves) allowed us to determine the main types of ice structure, such as monolithic ice, fast ice and hummocky ice. Statistical evaluation of the variation of reflected wave amplitudes from the ice cover allowed us to reveal the nature of the homogeneity of the set of amplitude values depending on the ice structure. As a result, an algorithm for processing and interpreting large volumes of airborne GPR data was developed, making it possible to make a reliable assessment of the thickness and structure of river ice cover, as well as to map the spatial distribution of its heterogeneities in the river channel. The information obtained about the state of river ice cover can be used for engineering-geophysical surveys, operation of ice crossings, substantiation of decisions on the application of preventive measures to destroy thick ice in the jam-prone river sections in order to safely pass the spring flood waters.

Polarimetric Airborne Radar Sounding as an Approach to Characterizing Subglacial Röthlisberger Channels

Conventional airborne radar sounding techniques are well suited to the detection and characterization of flat-lying, specular subglacial water bodies. However, topographically positive, diffusively scattering Rthlisberger (R-)channels are more difficult to image, while also exerting substantial control on basal friction and ice dynamics. As subglacial R-channels share geometrical similarities with targets of interest in polarimetric ground-penetrating radar studies (i.e., cylindrical pipes), in this study we investigate whether similar concepts can be adapted to detect and characterize R-channels. While closed form analytical solutions exist for the scattering widths of perfect electrically conducting (PEC) and dielectric circular cylinders, the insight they provide for the polarimetric response of half-cylinder R-channels is limited. As such, a series of modeling experiments have been performed to characterize the scattering widths of half cylinders. Our results demonstrate that scattering from subglacial R-channels depends on numerous factors including the polarization and frequency of the incident radar wave, the size of the R-channel, and the relative orientation of the R-channel to a pair of orthogonally oriented, linearly polarized radar antennas. The results imply that patterns in the like-polarized echo powers across the signal bandwidth may be useful in inferring R-channel existence and possibly estimate R-channel size. However, as differences in scattering width are small and decrease with increasing misalignment between the acquisition system antennas and R-channel strike, achieving a high degree of radiometric resolution and stability should be a driving factor in polarimetric radar system design.

Integrated Ground Penetrating Radar and Electrical Resistivity Study to Explore Such Basrah Low Resistivity Soils for Engineering Purposes, Southern Iraq

A total of 45 ground penetrating radar profiles have been conducted in Basrah City, Southern Iraq, to detect buried utilities in such soils which have not been tested before. This study tries to explore how much this technique can be useful for Basrah low resistivity soils during arid and humid seasons. In Basrah University Campus (silty clay soil) and Basrah Sport City (silty sand soil), 37 and 8 ground penetrating radar profiles were achieved inside these locations respectively. Vertical electrical sounding (Schlumberger array) and electrical profiling (Wenner array) were also used in compatibility with radar surveys side by side in all sites. Here, radargrams do not reveal much more details about the subsurface conditions because of the moisture content and soil characterizations. The actual penetrating depth of 250 and 500 MHz antennas are limited to 1.4 and 0.4 m respectively due to the soil total dissolved solids of about 6790 ppm. The tests suggest that the 250 MHz antenna is somewhat better than the 500 MHz one for detecting the shapes and depths of the buried bodies in silty clay soils during rainy or even arid periods. In Basrah Sport City (500 MHz) antenna, the radargram wave signals are not good for more than 2.5 m depth, and this antenna, rather than the 250 MHZ one is suitable for silty sand soil type.

Identification of buried historical mineshaft using ground-penetrating radar

Buried historical mineshafts constitute significant sinkhole hazards and sources of geotechnical risks. The locations of buried mineshafts on old mining maps are prone to inaccuracies. An efficient way to limit these inaccuracies is to use geophysical methods. However, their effectiveness strongly depends on the local survey conditions.The aim of the study was to identify the buried 14th century Wielki mineshaft in Bochnia Salt Mine, a UNESCO Worldwide Heritage Site, Poland. The need to locate this shaft was due to the following reasons. Firstly, the Bochnia Salt Mine had difficulties with water flowing into the workings from the supposed location of the Wielki mineshaft. The shaft area was one of the most waterlogged in the salt mine's terrain. An urgent task was to determine the shaft's exact location to implement a waterproof barrier to protect the historic mine workings. Secondly, the modernisation of the market square in Bochnia required clarification of the location of the Wielki mineshaft and checking as to whether it posed a sinkhole hazard to the terrain surface. Another important reason for locating the medieval shaft was its archaeological value.A ground surface and borehole ground-penetrating radar (GPR) study and geological-engineering recognition using boreholes were employed to indicate the location of the Wielki shaft. The anthropogenic layer of heterogeneous material and the urbanised site resulted in challenges with regard to detecting evident georadar anomalies. Several dozen intersecting GPR profiles were gathered in the research area using 250 MHz and 100 MHz antennae. The initial surface GPR results, indicative of the GPR anomaly, were consolidated by cored borehole investigation and a borehole GPR study. In particular, the presence of a void, loosened zones, and wooden fragments of the shaft lining was confirmed in the inclined control borehole. Following our classification of typical causes of the occurrence of sinkholes over buried mineshafts, the consolidation of backfill material in a mineshaft was determined as the cause of the sinkhole originated above the Wielki shaft (type B sinkhole). Destruction of the shaft's wooden cap may result in the occurrence of a sinkhole on the ground surface. Therefore, the void was backfilled and a hydraulic barrier was consequently made to stop the seepage of water into the Bochnia Salt Mine's historic workings.This case study demonstrates that surface and borehole GPR surveying integrated with borehole data offers the possibility of obtaining the high-resolution data needed to accurately locate an old buried mineshaft in an urbanised area. The GPR anomaly was indirectly detected on the basis of the deflection of the boundary between the natural ground and an anthropogenic layer with sufficient contrast in their electromagnetic properties. This approach can be useful wherever the georadar penetration range is limited by high attenuation and dispersiveness of the anthropogenic layer.

Ground-penetrating radar imaging reveals glacier's drainage network in 3D

Abstract. Hydrological systems of glaciers have a direct impact on the glacier dynamics. Since the 1950s, geophysical studies have provided insights into these hydrological systems. Unfortunately, such studies were predominantly conducted using 2D acquisitions along a few profiles, thus failing to provide spatially unaliased 3D images of englacial and subglacial water pathways. The latter has likely resulted in flawed constraints for the hydrological modelling of glacier drainage networks. Here, we present 3D ground-penetrating radar (GPR) results that provide high-resolution 3D images of an alpine glacier's drainage network. Our results confirm a long-standing englacial hydrology theory stating that englacial conduits flow around glacial overdeepenings rather than directly over the overdeepening. Furthermore, these results also show exciting new opportunities for high-resolution 3D GPR studies of glaciers.

Reviewing methods for determination of Dielectric Constant required to Calibrate GPR Study for Asphalt Layers

Ground Penetrating Radar (GPR) is a non-invasive technique developed substantially in the recent years. Initially, GPR technology was applied to natural ground to explore the sub-surface conditions and identify the anomalies in it. Now it has become a well-accepted technique to investigate any kind of materials such as wood, ice, concrete, asphalt etc. The calibration of GPR equipment is most important prerequisite criteria before data collection for accurate investigation of pavement subsurface features. During calibration, the velocity of radar waves will be calibrated in contrast to subjected material as whole examination is governed on the basis of it. The basic dielectric properties required as a prerequisite while using GPR system are dielectric permittivity, electrical conductivity along with magnetic permeability. The dielectric constant affects the velocity of transmitting wave as inverse proportion i.e. velocity decreases with an increase in dielectric constant and vice-versa. Considering the principle, the detailed study of pavements requires understanding and estimation of ‘bulk’ dielectric constant. The heterogeneous conditions of pavement actually obscure the straightforwardness of analysis and therefore estimation of a ‘bulk’ dielectric constant value becomes essential. There are several methods to compute the dielectric constant of asphaltic layers, which are developed by different researchers, and these are discussed briefly in this paper. The paper tries to put forward the merits and demerits of these methods and to identify the most appropriate one suiting to Indian conditions.