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Methodologies for conducting highway infrastructure inspection activities are experiencing a substantial change with the proliferation of technology. Instead of relying on destructive testing methods to perform inspections, state departments of transportation (DOTs) use a wide range of non-destructive testing (NDT) methods for inspecting highway construction projects and assets. However, the varying approaches adopted among the state DOTs can lead to confusion and inconsistency. Therefore, this study aims to provide a comprehensive and systematic overview of several NDT methods available for inspection activities used across the nation. A national survey of 50 state DOTs was conducted to collect data. The results showed that the typical NDT methods used for highway construction inspection include nuclear density gauges, dynamic test loading for piles, cross-hole sonic logging for drilled shafts, surface profile measuring systems, ground-penetrating radar, and ultrasonic testing. The typical inspection activities during construction using NDT are in situ material characterization, foundation investigation, structural inspection, and bridge deck deterioration. The top inspection activities involving NDT technologies during asset maintenance include structural inspection, automated pavement distress measurements, and identification of fracture damage. This study contributes to the literature by summarizing and analyzing the NDT technologies for highway infrastructure inspection activities.
Le et al. (Mon,) studied this question.