scholarly journals AN EXAMPLE OF COMPLIANCE VERIFICATION OF PAVEMENT PROJECT SPECIFICATIONS BY MEANS OF GEOPHYSICS

2018 ◽  
Vol 36 (1) ◽  
pp. 33
Author(s):  
Carolina Narjara Mazzini Amaral ◽  
Lúcia Maria da Costa e Silva

ABSTRACT. The most important information about asphalt pavement is layer thickness. This information indicates whether or not the project specifications were met, and can also direct future recovery plans. Verifying these data relies on destructive techniques, such as boreholes, which may be expensive or even render verification unfeasible. Using the electromagnetic geophysical method known as ground penetrating radar (GPR), it is possible to verify compliance with pavement project specifications in an efficient and non-destructive way. We present an example of the use of GPR for this purpose obtained on a paved road at the campus of the Universidade Federal do Pará (UFPA), in Brazil. The GPR survey enabled individual pavement layers be identified. The comparison of the thickness of these layers, and those found in a borehole drilled during the GPR survey, with the thickness specified by the construction project plans, showed significant discrepancies. Keywords: ground penetrating radar, GPR, asphalt layer thickness. RESUMO. As informações mais importantes sobre o pavimento asfáltico são a espessura de suas camadas. Estas quantidades indicam se as especificações do projeto foram atendidas e podem também direcionar planos futuros de recuperação. A verificação desses dados depende de técnicas destrutivas, tais como perfurações, que podem encarecê-la ou até torná-la inviável. Com o método geofísico GPR é possível verificar o cumprimento das especificações de projeto de pavimentação asfáltica de maneira eficiente e não destrutiva. Apresentamos um exemplo obtido em uma estrada pavimentada no campus da Universidade Federal do Pará (UFPA, Brasil) que permitiu a identificação das camadas do pavimento com o GPR. A comparação dessas espessuras e daquelas obtidas por meio de um furo perfurado durante o levantamento GPR com as espessuras especificadas pelo projeto de construção mostram discrepâncias significativas. Palavras-chave: radar de penetração do solo, GPR, espessura de pavimentação asfáltica.

2018 ◽  
Vol 10 (0) ◽  
pp. 1-5
Author(s):  
Andrius Baltrušaitis ◽  
Audrius Vaitkus

The optimum density and air-voids content of asphalt pavement layers are among the main indicators of the durability of asphalt road pavement. The asphalt pavement with insufficient density is less resistant to traffic loading and the damaging effects caused by water. Air-voids ensure the durability of asphalt pavement and the accumulation of free bitumen during a period of hot weather. At present, the main ways to control the quality of compaction and the content of air-voids is to drill core specimens and test them in the laboratory. This method is expensive, it damages the road surface, and the quality of asphalt pavement is verified only at several points. With the rapid development of new technologies, it is necessary to evaluate and to apply innovative non-destructive methods, allowing us to determine the qualitative characteristics of asphalt pavement across the entire length of the road without causing the damage to the road surface and at lower costs. This article describes the use of Ground Penetrating Radar to determine asphalt pavement density and air-voids content provides an overview of global practices and feasibility analysis on the application of Ground Penetrating Radar on the roads of Lithuanian. Santrauka Asfalto dangos sluoksnių optimalus tankis ir oro tuštymių kiekis yra vieni iš pagrindinių dangos ilgaamžiškumo rodiklių. Nepakankamo tankio danga yra mažiau atspari automobilių eismo apkrovoms ir žalingam vandens poveikiui. Oro tuštymės užtikrina dangos ilgaamžiškumą ir laisvojo bitumo akumuliavimą karštuoju metų laikotarpiu. Šiuo metu pagrindinis būdas kontroliuoti sutankinimą ir oro tuštymių kiekį yra gręžti kernus ir juos bandyti laboratorijoje. Šis metodas yra brangus, gadinama kelio danga ir asfalto dangos kokybė patikrinama tik keliuose taškuose. Sparčiai vystantis technologijoms būtina įvertinti ir taikyti inovatyvius neardančiuosius metodus, leidžiančius kokybinius asfalto dangos rodiklius nustatyti neardant dangos, išilgai viso kelio ir mažesnėmis sąnaudomis. Šiame straipsnyje pateikta georadaro (angl. Ground Penetrating Radar) taikymo asfalto dangai sutankinti ir oro tuštymių kiekiui nustatyti pasaulinės praktikos apžvalga ir panaudojimo Lietuvos automobilių keliuose galimybių analizė.


2014 ◽  
Vol 501-504 ◽  
pp. 847-851
Author(s):  
Che Way Chang ◽  
Chen Hua Lin ◽  
Shyi Lin Lee ◽  
Ping Huang Chen ◽  
Ching Cheng Jen ◽  
...  

Ground Penetrating Radar (GPR) is a high efficiency technology to detect the cylindrical medium in the concretes material. The electromagnetic wave is incidental to double-rebar, and measures the reflection signal behaviors from energy zone. The results from the reflection signal of electromagnetic wave of the reinforcement concretes allow evaluating the radius of double-bar (1.6cm, 1cm). A physical model can effectively measure the radius of double-bar by the result of electromagnetic wave reflex behavior analysis. The results indicate that, this techology is capable of estimating the reinforcing double-bar radius to within 6%.


2021 ◽  
Vol 13 (18) ◽  
pp. 3696
Author(s):  
Yuri Álvarez López ◽  
María García-Fernández

Ground Penetrating Radar (GPR) has become one of the key technologies in subsurface sensing and, in general, in Non-Destructive Testing (NDT), since it is able to detect both metallic and nonmetallic targets [...]


2010 ◽  
Vol 21 ◽  
pp. 399-417
Author(s):  
Mardeni Bin Roslee ◽  
Raja Syamsul Azmir Raja Abdullah ◽  
Helmi Zulhaidi bin Mohd Shafr

2020 ◽  
Author(s):  
Livia Lantini ◽  
Fabio Tosti ◽  
Iraklis Giannakis ◽  
Kevin Jagadissen Munisami ◽  
Dale Mortimer ◽  
...  

<p>Street trees are widely recognised to be an essential asset for the urban environment, as they bring several environmental, social and economic benefits [1]. However, the conflicting coexistence of tree root systems with the built environment, and especially with road infrastructures, is often cause of extensive damage, such as the uplifting and cracking of sidewalks and curbs, which could seriously compromise the safety of pedestrians, cyclists and drivers.</p><p>In this context, Ground Penetrating Radar (GPR) has long been proven to be an effective non-destructive testing (NDT) method for the evaluation and monitoring of road pavements. The effectiveness of this tool lies not only in its ease of use and cost-effectiveness, but also in the proven reliability of the results provided. Besides, recent studies have explored the capability of GPR in detecting and mapping tree roots [2]. Algorithms for the reconstruction of the tree root systems have been developed, and the spatial variations of root mass density have been also investigated [3].</p><p>The aim of this study is, therefore, to investigate the GPR potential in mapping the architecture of root systems in street trees. In particular, this research aims to improve upon the existing methods for detection of roots, focusing on the identification of the road pavement layers. In this way, different advanced signal processing techniques can be applied at specific sections, in order to remove reflections from the pavement layers without affecting root detection. This allows, therefore, to reduce false alarms when investigating trees with root systems developing underneath road pavements.</p><p>In this regard, data from trees of different species have been acquired and processed, using different antenna systems and survey methodologies, in an effort to investigate the impact of these parameters on the GPR overall performance.</p><p> </p><p><strong>Acknowledgements</strong></p><p>The authors would like to express their sincere thanks and gratitude to the following trusts, charities, organisations and individuals for their generosity in supporting this project: Lord Faringdon Charitable Trust, The Schroder Foundation, Cazenove Charitable Trust, Ernest Cook Trust, Sir Henry Keswick, Ian Bond, P. F. Charitable Trust, Prospect Investment Management Limited, The Adrian Swire Charitable Trust, The John Swire 1989 Charitable Trust, The Sackler Trust, The Tanlaw Foundation, and The Wyfold Charitable Trust. This paper is dedicated to the memory of our colleague and friend Jonathan West, one of the original supporters of this research project.</p><p> </p><p><strong>References</strong></p><p>[1] J. Mullaney, T. Lucke, S. J. Trueman, 2015. “A review of benefits and challenges in growing street trees in paved urban environments,” Landscape and Urban Planning, 134, 157-166.</p><p>[2] A. M. Alani, L. Lantini, 2019. “Recent advances in tree root mapping and assessment using non-destructive testing methods: a focus on ground penetrating radar,” Surveys in Geophysics, 1-42.</p><p>[3] L. Lantini, F. Tosti, Giannakis, I., Egyir, D., A. Benedetto, A. M. Alani, 2019. “A Novel Processing Framework for Tree Root Mapping and Density Estimation using Ground Penetrating Radar,” In 10th International Workshop on Advanced Ground Penetrating Radar, EAGE.</p>


2019 ◽  
Vol 11 (23) ◽  
pp. 2814 ◽  
Author(s):  
Sossa ◽  
Pérez-Gracia ◽  
González-Drigo ◽  
Rasol

Corrosion is a significant damage in many reinforced concrete structures, mainly in coastal areas. The oxidation of embedded iron or steel elements degrades rebar, producing a porous layer not adhered to the metallic surface. This process could completely destroy rebar. In addition, the concrete around the metallic targets is also damaged, and a dense grid of fissures appears around the oxidized elements. The evaluation of corrosion is difficult in early stages, because damage is usually hidden. Non-destructive testing measurements, based on non-destructive testing (NDT) electric and magnetic surveys, could detect damage as consequence of corrosion. The work presented in this paper is based in several laboratory tests, which are centered in defining the effect of different corrosion stage on ground penetrating radar (GPR) signals. The analysis focuses on the evaluation of the reflected wave amplitude and its behavior. The results indicated that an accurate analysis of amplitude decay and intensity could most likely reveal an approach to the state of degradation of the embedded metallic targets because GPR images exhibit characteristics that depend on the effects of the oxidized rebar and the damaged concrete. These characteristics could be detected and measured in some cases. One important feature is referred to as the reflected wave amplitude. In the case of corroded targets, this amplitude is lower than in the case of reflection on non-oxidized surfaces. Additionally, in some cases, a blurred image appears related to high corrosion. The results of the tests highlight the higher amplitude decay of the cases of specimens with corroded elements.


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