Evaluation of Nondestructive Methods for Determining Pavement Thickness

This study aims at evaluating reinforced concrete (RC) bridge elements using ultrasonic pitch and catch (UPC) non-destructive testing (NDT) technique. A validation reinforced concrete slab with two embedded layers of rebars and artificial defects (voids, honeycombs, and debondings) was designed and tested. A commercial UPC NDT device (hereafter called “UPC device”), which is based on the ultrasonic shear-wave test method using dry-point-contact transmitting and receiving transducers in a “pitch-catch” configuration, was used to map internal defects of the validation RC slab. The recorded data from the UPC device was analyzed using a modified synthetic aperture focusing technique (SAFT). A software was developed to reconstruct 2-D images of the RC slab cross-sections using novel signal filtering and processing techniques. The results revealed that the 2-D image reconstructed from the developed software accurately exhibited locations and horizontal dimensions of the steel rebars, voids, and debondings. In addition, the developed software was capable to provide much higher resolution and sharper images of the anomalies inside the RC slab compared to the UPC device’s proprietary imaging software.

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“…These discrepancies may be caused by the uneven surface of the RC slabs. Similar observations were reported by other researchers [8,23]. In Fig.…”

Section: Resultssupporting

confidence: 92%

Ultrasonic pitch and catch technique for non-destructive testing of reinforced concrete slabs

Zatar

Hai

Nghiem

2020

J Infrastruct Preserv Resil

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“…Destructive concrete sampling is done sparingly so as to not compromise the structural capacity of the structure. Until recently, nondestructive testing (NDT) devices for concrete existed, but reliability, accuracy, device specificity, size, and cost were some of the reasons why the use of NDT devices for concrete testing was not widespread (1). With current NDT devices that quickly, inexpensively, and reliably measure concrete thickness, NDT could be used instead of destructive concrete samples to collect thickness data for concrete infrastructure.…”

Section: Concrete Pavement Thickness Variation Assessment With Cores and Nondestructive Testing Measurementsmentioning

confidence: 99%

“…The thickness measurement corresponds to the center of the concrete base interface reflection. The measurement accuracy of MIRA is illustrated in Figure 3, which is a combination of data from two studies (1,7).…”

Section: Nondestructive Measurement Of Concrete Pavement Thicknessmentioning

confidence: 99%

Concrete Pavement Thickness Variation Assessment with Cores and Nondestructive Testing Measurements

Vancura

Khazanovich

Barnes

2013

Transportation Research Record: Journal of the Transportation R

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Concrete pavement thickness data were collected from sections of two concrete pavements with a nondestructive testing (NDT) device and by measuring concrete core thickness. The NDT device allowed thickness measurements every 15 ft compared with 1,000 ft for each core. Comparison of the core and NDT data showed that core thickness data do not capture the extreme peaks and valleys of pavement thickness variation. Further analysis of the core and NDT thickness data with the Minnesota Department of Transportation's concrete pavement thickness specifications highlighted that contractor pay deductions based on thickness deficiencies were not realized. Autocorrelation analysis of the data showed that concrete pavement thickness variation is not random but is correlated to thicknesses of lag between 30 and 270 ft. This correlation lag is a starting point for answering the question, how often must a thickness measurement be taken to accurately characterize the thickness variation of a concrete pavement?

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“…While the use of multi-offset methods has been somewhat limited for pavement moisture quantification, this approach has been used by many authors to determine the depth and permittivity of pavement layers , Mesher et al, 1995, Edwards and Mason, 2011, Hamrouche and Saarenketo, 2014, Zhao and Al-Qadi, 2016, Liu and Sato, 2014, De Pue et al, 2016, Hugenschmidt, 2000, Lahouar et al, 2002. To enable efficient data collection using off-the-shelf equipment, some authors have combined the …”

Section: Other Uses Of Multi-offset Techniquesmentioning

confidence: 99%

Characterising moisture within unbound granular pavements using multi-offset Ground Penetrating Radar

Muller¹

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Moisture has a significant influence on the performance and durability of unbound granular (UBG) pavements with thin bituminous surfacings, which form the vast majority of all-weather Australian roads. Techniques for measuring pavement moisture content are therefore important to quantify its influence on structural performance, enable early detection of problem areas, and to assess the condition of flood-affected pavements.Conventional techniques, however, require invasive probes or physical sampling which are impractical for large-scale investigations. Ground Penetrating Radar (GPR) techniques show promise, yet existing methods achieve only qualitative estimates, involve simplifications that limit accuracy or require complicated or laborious data analysis. The aim of this research was to develop a semi-automated approach using multi-offset GPR to quantitatively estimate the moisture content and depth of UBG pavement layers while maintaining data analysis simplicity.The research made use of a new type of 3-dimensional (3D) GPR technology able to continuously collect ground-coupled multi-offset gathers across the road while travelling at up to traffic speeds. To enable development of analysis methods prior to equipment completion, numerical simulations were used to model the expected response for typical pavement configurations. These data were used to test a semi-automated approach using interface tracking and conventional multi-offset geophysical analysis methods.They were also used to develop two novel self-correcting analysis techniques, Interface Matching (IM) and Ray-path Modelling (RM), which use migration and tomographic approaches, respectively.A permittivity characterisation approach, later called modified free-space (MFS), was also adapted for laboratory characterisation of UBG materials. It was used to calibrate petro-physical relations for these materials that enable pavement moisture estimates from the GPR measurements. As the MFS approach departs from conventional freespace methods, numerical modelling and a series of laboratory experiments were used to assess measurement accuracy and to determine the influence of sample edges, aspect ratio, and depth and antenna separation on the measurements. These investigations demonstrated that the MFS approach was suitable using the proposed equipment, sample sizes and for the range of relative permittivity values likely to be encountered. It also produced results that compared well with established apparatus over the frequency range relevant to pavement GPR.iii Measurements using this approach were also compared with conventional time-domain reflectometry (TDR) and common-offset GPR measurements of moisture-varying and density-varying UBG samples. The comparison showed similar results for most samples, although TDR reported lower relative permittivity values for drier and lowerdensity materials.Upon completion of the 3D GPR equipment, a revised analysis approach called Raypath Modelling-Semblance (RM-S) was developed. It was used to analyse multi-off...

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Evaluation of Nondestructive Methods for Determining Pavement Thickness

Cited by 14 publications

References 5 publications

Ultrasonic pitch and catch technique for non-destructive testing of reinforced concrete slabs

Ultrasonic pitch and catch technique for non-destructive testing of reinforced concrete slabs

Concrete Pavement Thickness Variation Assessment with Cores and Nondestructive Testing Measurements

Characterising moisture within unbound granular pavements using multi-offset Ground Penetrating Radar

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