Determination of the applicability and limits of void and delamination detection in concrete structures using infrared thermography

Cotič, Patricia; Kolarič, Dejan; Bosiljkov, Vlatko; Jagličić, Zvonko

doi:10.1016/j.ndteint.2015.05.003

Cited by 89 publications

(68 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The applicability and limits of void and delamination detection in concrete structures using infrared thermography was performed by Patricia Cotic et al in 2015 [18]. They conducted experiments of 51 artificially defects with sizes from 1.2 to 10 cm located at depths from 0.5 to 12.5 cm in concrete, using active infrared thermography.…”

Section: Related Workmentioning

confidence: 99%

“…This technique gives reliable results in the evaluation of the near-surface region with the depth of defects less than 10 cm [8,14]. In several researches, when the ratio between the size and the depth of delamination (so-called width-to-depth ratio or WTDR) is smaller than 2.0, the delamination was considered undetectable [15,16], while other authors stated that delamination with a WTDR smaller than 2.0 could be detected using advanced image processing techniques, as discussed in Section 2 [3,6,11,[17][18][19]. In this study, the Long Pulsed Thermography (LPT) technique, one of the most common methods of active infrared thermography, is used to clarify the effects of depth, heating time, and steel bars on the detectability capacity of delamination inside a concrete specimen.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Detectability of Delamination in Concrete Structure Using Active Infrared Thermography in Terms of Signal-to-Noise Ratio

et al. 2018

View full text Add to dashboard Cite

Detecting subsurface delamination is a difficult and vital task to maintain the durability and serviceability of concrete structure for its whole life cycle. The aim of this work was to obtain better knowledge of the effect of depth, heating time, and rebar on the detectability capacity of delamination. Experimental tests were carried out on a concrete specimen in the laboratory using Long Pulsed Thermography (LPT). Six halogen lamps and a long wavelength infrared camera with a focal plane array of 640 × 480 pixels were used as the heat source and infrared detector, respectively. The study focused on the embedded imitation delaminations with the size of 10 cm × 10 cm × 1 cm, located at depths varying from 1 to 8 cm. The signal-to-noise ratio (SNR) was applied as a criterion to assess the detectability of delamination. The results of this study indicate that as the provided heating time climbed, the SNR increased, and the defect could be identified more clearly. On the other hand, when using the same heating regime, a shallow delamination displayed a higher SNR than a deeper one. The moderate fall of the SNR in the case of imitating defect located below reinforced steel was also observed. The absolute contrast was monitored to determine the observation time, and the nondimensional prefactor k was empirically proposed to predict the depth of delamination. The mean absolute percentage error (MAPE) was used to quantitatively evaluate the difference between forecasted and real depth, which evaluation confirmed the high reliability of the estimated value of the prefactor k.

show abstract

Section: Related Workmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Detectability of Delamination in Concrete Structure Using Active Infrared Thermography in Terms of Signal-to-Noise Ratio

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Let us consider a reinforced concrete element, for example a vertical one such as a pillar or a wall, in which a segregation phenomenon occurred during hardening, determining the formation of a volume full of cavities that can be assimilated by size to the MC of the test. This kind of defect is commonly simulated by means of embedded voids [58][59][60][61][62] as the MC of the test. Figure 16 shows the overestimate of the usable cross section of the element net of the section of the defect as a function of the size of the defect and of the I index reported in Table 3.…”

Section: Commentsmentioning

confidence: 99%

“…As an example and by accepting a rough calculation, if the element is loaded by axial compression the overlap of the resistant section results in a corresponding overestimate of the section capacity load. Similarly, if we consider the presence of a delamination or detachment area that can be assimilated to the plastic elements P 1,2,3 of the test, as is common in literature [61][62][63][64], depending on the spacing and the position of the measurement points the defect is not detected or it is overestimated even by 150%. Additionally, in this case there can be repercussions on the correct evaluation of the structural integrity and therefore on the refurbishment planning.…”

Section: Commentsmentioning

confidence: 99%

Concrete Defects Sizing by Means of Ultrasonic Velocity Maps

Concu

Trulli

2018

Buildings

View full text Add to dashboard Cite

The paper illustrates the results of an experimental test which intends to check the efficacy of ultrasonic testing (UT) in detecting anomalies inside concrete elements. For this purpose, UT has been carried out on a small concrete wall having different defects deliberately settled inside the wall during casting. A grid of several measurements points has been arranged on the wall surfaces and for each point the ultrasonic signal has been acquired after passing through the thickness of the wall and the propagation velocity V has been extracted and analyzed. A graphic representation of V distribution has been implemented by a map where each pixel identifies one measurement point and is representative of its neighborhood. This map highlights areas with different velocity values, and allows to visually detect areas having particularly low velocity. The matching between the low-velocity areas and the artificial defects has been analyzed, and the level of accuracy of the V map in detecting and sizing the concrete inner defects has been discussed with reference to different spacing of the grid points. Finally, some considerations regarding the choice of the most suitable measurements grid have been addressed.

show abstract

“…Several NDT methods, such as the ultrasonic pulse velocity method [3,4], acoustic emission [5,6,7,8], infrared thermography [9,10] and the pulse-echo method [11], have been applied in structural damage detection. These methods have shown various degrees of success in assessing structural damage severity.…”

Section: Introductionmentioning

confidence: 99%

Concrete Infill Monitoring in Concrete-Filled FRP Tubes Using a PZT-Based Ultrasonic Time-of-Flight Method

Luo

Hei

et al. 2016

Sensors

View full text Add to dashboard Cite

Concrete-filled fiber-reinforced polymer tubes (CFFTs) have attracted interest for their structural applications in corrosive environments. However, a weak interfacial strength between the fiber-reinforced polymer (FRP) tube and the concrete infill may develop due to concrete shrinkage and inadequate concrete compaction during concrete casting, which will destroy the confinement effect and thereby reduce the load bearing capacity of a CFFT. In this paper, the lead zirconate titanate (PZT)-based ultrasonic time-of-flight (TOF) method was adopted to assess the concrete infill condition of CFFTs. The basic idea of this method is that the velocity of the ultrasonic wave propagation in the FRP material is about half of that in concrete material. Any voids or debonding created along the interface between the FRP tube and the concrete will delay the arrival time between the pairs of PZT transducers. A comparison of the arrival times of the PZT pairs between the intact and the defected CFFT was made to assess the severity of the voids or the debonding. The feasibility of the methodology was analyzed using a finite-difference time-domain-based numerical simulation. Experiments were setup to validate the numerical results, which showed good agreement with the numerical findings. The results showed that the ultrasonic time-of-flight method is able to detect the concrete infill condition of CFFTs.

show abstract

Determination of the applicability and limits of void and delamination detection in concrete structures using infrared thermography

Cited by 89 publications

References 21 publications

Detectability of Delamination in Concrete Structure Using Active Infrared Thermography in Terms of Signal-to-Noise Ratio

Detectability of Delamination in Concrete Structure Using Active Infrared Thermography in Terms of Signal-to-Noise Ratio

Concrete Defects Sizing by Means of Ultrasonic Velocity Maps

Concrete Infill Monitoring in Concrete-Filled FRP Tubes Using a PZT-Based Ultrasonic Time-of-Flight Method

Contact Info

Product

Resources

About