Adoption of periodic or continuous monitoring strategies to assess condition state of infrastructure elements is a vital part of service life management (SLM). NDT methods are increasingly seen as an attractive and viable strategy to support condition monitoring. Over the last 15 years, the LEME research group at UFRGS has investigated several aspects related to the use of the ultrasonic pulse velocity (UPV) method and its potential for real field applications. One of the main advances involved the development of artificial neural network (ANN) models for correlating compressive strength and UPV measurements. Another examined problem was how to deal with the large amount of raw data derived from inspection of large structures. Several studies were carried out to check different mapping techniques, as reported by Lorenzi et al. 2011. This paper relates one investigation where UPV and rebound hammer (RH) measurements were collected from a beam containing several induced defects, simulated using different materials. The results were processed using a mapping strategy, which indicated suspicious points where core extraction was undertaken. All cores taken from points derived from UPV results were found to have flaws providing evidence that this may be a suitable tool to assess concrete structures, when data is properly interpreted.

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.

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ResumoApplication of Nondestructive Testing ( NDT) is an interesting strategy to monitor reinforced concrete structures conditions, especially when occur problems like admixture errors, mixing problems, conveying or placing of concrete . Among the NDT methods applicable to concrete, the Ultrasonic Pulse Velocity has been used in various fields of civil engineering due to the ease of operation, low cost, test velocity and that using this test normally do not need repair the surface analyzed. This work aims to study the influence that certain technological variables have on the results obtained through the UPV. Two concrete elements were cast at the laboratory. One element with reinforcement and another without reinforcement. Inside these elements were introduced objects to reproduce possible concrete damages. To facilitate the analysis the results are represent through several images generated by an image software and an statistical analysis software. This study confirm that the correct choice of test parameters is crucial to have a right interpretation.Keywords: nondestructive testing, ultrasonic pulse velocity, reinforced concrete structures.A aplicação de Ensaios Não Destrutivos (END) é uma estratégia interessante para monitorar o estado de conservação das estruturas de concreto armado, principalmente quando ocorrem erros de dosagem, problemas na mistura, transporte ou lançamento do concreto. Dentre os métodos de END, aplicáveis ao concreto, o método de ensaio da Velocidade de Propagação do Pulso Ultrassônico (VPU) vem sendo utilizado comumente em diversas áreas da Engenharia Civil, devido à facilidade da operação, ao seu baixo custo, à rapidez na execução dos testes e à ausência de danos ao material analisado. Este trabalho visa estudar a influência que determinadas variáveis tecnológicas exercem sobre os resultados obtidos através dos ensaios de VPU. Foram moldados em laboratório dois elementos de concreto, com dimensões próximas a estruturas reais. Um elemento com armadura nas duas faces e outro sem armadura, nos quais foram introduzidos objetos para reproduzir possíveis falhas de concretagem. De modo a facilitar a análise dos dados, os resultados são apresentados por meio de imagens geradas através de programas computacionais e análises estatísticas. Através deste estudo verificou-se que a escolha dos parâmetros de ensaios é fator crucial para que se tenha uma interpretação correta dos resultados.Palavras-chave: ensaios não destrutivos, velocidade de propagaçao do pulso ultrassônico, estruturas de concreto armado.

Pervious concrete may be used for stormwater management since it allows the water to pass through its interconnected macropores into stormwater systems or soils below. However, there is a need for additional standards related to pervious concrete prior to its widespread use, and there are many aspects related to mix design for desired properties, compaction methods, and test procedures that are not yet completely understood. These variables may significantly affect the functional and mechanical performance of the material. In this paper, mix designs and test specimen preparation techniques were evaluated. The IBRACON method for mixture design was used to obtain the mixture proportions and the calculated density for the desired porosity of 25%. In addition, two different types of specimens (cast or cored) and compaction methods (roller or Proctor hammer compacted) were performed. The density of each specimen was controlled to obtain the same calculated density. Several tests were conducted to compare the following variables: density, porosity, surface infiltration rate, permeability and compressive strength. Additionally, the effects of mortar capping versus neoprene-rubber caps on compressive strength measurements of pervious concrete were evaluated. The experimental results showed that cast specimens have more consistent results than cores. The design method studied with strict control of density was efficient to obtain the desired porosity mainly for cast specimens. The roller leads to a more compacted top surface resulting in a decrease in the infiltration rate and permeability of the cores. The mortar capping method is more consistent than the other.