Analyzing two different data processing strategies for monitoring concrete structures using ultrasonic pulse velocity

Abstract

RESUMENO crescente aumento dos sintomas de deterioração precoce em estruturas de concreto serve de argumento para o desenvolvimento e validação de técnicas de monitoramento do estado de conservação das mesmas. Além disto, fornecerem dados para estimar a vida útil das estruturas. A utilização de Ensaios Não Destrutivos permite a prevenção e o controle da deterioração de estruturas de concreto, sem danificar o material. O ensaio de Velocidade de Propagação do Pulso Ultrassônico (VPU) é uma forma bastante eficaz para realizar o controle de qualidade. Utilizando os resultados do ensaio de VPU é possível verificar a uniformidade de concreto, acompanhar sua deterioração, detectar falhas e vazios internos e, por meio de uma comparação com as amostras de referência, até mesmo estimar a resistência à compressão. Os resultados obtidos neste trabalho indicam que através do mapeamento superficial consegue-se analisar e visualizar os resultados dos ensaios de VPU.Palabras Clave: concreto; ultrassom; mapeamento superficial; análise estatística.ABSTRACTThe increasing number of early deterioration symptoms found in relatively new concrete structures provides a strong argument for the development and validation of techniques to monitor the condition state of concrete elements and provide data to estimate the potential service life. The use of NDT monitoring techniques is an important way to prevent and control the deterioration of concrete structures without damaging the material. Ultrasonic Pulse Velocity (UPV) measurements seem to be a quite effective way to perform quality control, since this reliable and flexible test method allows an in-depth analysis of the material’s condition. Using UPV data it is possible to check the concrete uniformity, accompany the deterioration, detect internal flaws and voids and, by means of a comparison with reference specimens, even estimate the compressive strength. The results indicate that surface mapping seems to be a better way to analyze and visualize UPV results.Keywords: concrete; ultrasonic methods; surface mapping; statistical analysis.

Analysis of reinforced concrete structures through the ultrasonic pulse velocity: technological parameters involved

“…Exactly for this potentiality, the UPV has been the most investigated NDT in research in Structural Tests and Materials Laboratory of the Federal University of Rio Grande do Sul (LEME/UFRGS). In various research work conducted, on the field and in the laboratory, a technique of UPV was developed, mapping with indirect readings, and confirmed that the method, when properly employed, can offer ease of implementation, fast and suitable fault detection capability [3,4,5,6,7,8,9]. Several researches related to UPV and concrete.…”

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“…UPV propagation at concrete is very sensitive to the presence of flaws, cracks, or other discontinuities. The mapping was performed by indirect measurement technique which has proved appropriate to map the surfaces, allowing to detect voids and defects (Lorenzi, Reginato, Favero & Silva Filho, 2013), (Lorenzi, Caetano, Drunn & Silva Filho, 2003), (Lorenzi, Silva Filho, Caetano, Campagnolo & Strieder, 2004), (Lorenzi, Caetano & Silva Filho, 2005), (Lorenzi, Silva Filho, Campagnolo, Caetano & Fischer, 2006), (Lorenzi, Caetano, Campagnolo & Silva Filho, 2009), (Lorenzi, Lorenzi, Caetano & Silva Filho, 2010), (Lorenzi, Silva Filho, Campagnolo & Caetano, 2012), (Lorenzi, Silva Filho, Caetano & Chies, 2014), (Lorenzi, Caetano, Campagnolo, Lorenzi & Silva Filho, 2015).…”

Inspection and evaluation of air filled void inside reinforced concrete structure by non-destructive testing methods

“…This technique is the oldest of the NDT method for determine crack depth (Zoidis et al, 2013) based on the stress wave propagation technique by measuring the travel time of a compressional wave over a known path length. Due to the C P depends on the elastic constants and the mass density, it is possible to determine the uniformity or integrity of the concrete (Lorenzi et al, 2015). The testing principle is showed in Figure 5 below which represents different cases of ultrasonic pulses from one side to the other side.…”

“…The indirect and semi-direct mode results between the travel time and the distance between transducers which could be an error from point shifting; however, they are required to assess only side or corner of the structure which suitable with slabs, walls, and wider testing areas. The UPV method is an simple method for locating the defected area which have difference of concrete quality by creating the UPV contour mapping (Lorenzi et al, 2015). Nevertheless, the limitations of the UPV method need to access both sides of the structure surface, need smooth surface or using grease coupling for more accuracy, and cannot provide the depth of defects.…”

“…However, the main factor effected to the quality of underground void detection was service provider. Lorenzi et al (2015) researched that determine the quality of concrete was carried out by the UPV method. This method was worldwide used because the abilities of this method could check variation in structures, presence of physical damages, measure thickness, and change of physical properties of materials.…”