NDT Technology Introduction
Traditionally, an airport pavement is assessed through visual inspection of the surface, but this can be subjective and supplies little information about its structural condition. To assess the pavement structurally, the material must be characterized using tests performed on the material itself on-site and in the laboratory, obtained through cores, borings, and excavation pits. These destructive methods disrupt airport operations by shutting down the sections under investigation while samples are collected, on-site testing is conducted, and the damage is repaired. Depending on the scope of the investigation, the repairs can be extensive and costly.
The assessment of an airport pavement using NDT technologies does not involve the removal or destruction of pavement material. These technologies assess the functional and structural condition of the pavement under actual field conditions and leave the pavement intact, thus minimizing the disruption of airport operations. Utilizing multiple NDT methods allows the engineer to assess several aspects of the pavement system to ensure safe and efficient operations.
Airport pavement condition is separated into two categories: structural and functional. The structural condition is based on the physical and material characteristics of the system that deal with the strength of the pavement. Such properties include the pavement layer thicknesses and the moduli, which determine the load bearing capacity of the system and, thus, the levels of aircraft it can support.
The functional condition is based on the surface characteristics of the system that deal with the serviceability of the pavement. Such characteristics include surface roughness and skid resistance, which affects how an aircraft responds to the pavement. During takeoff, landing, and taxiing operations, surface irregularities can translate through the suspension of the aircraft, causing excessive vibrations that potentially impair safe operations or induce excessive stress and wear of the aircraft, leading to premature fatigue failure. In addition, interaction between the aircraft’s tires and the pavement surface determines the level of skid resistance, which is influenced by many factors. Poor surface friction can lead to more accidents on the ground.
NDT involves a wide variety of technologies that assess a spectrum of pavement properties. The ATR maintains a suite of NDT systems to conduct both structural and functional airport pavement evaluations in support of the FAA’s research objectives. FAA has also developed several computer programs to analyze the NDT data for use by engineers and researchers.
Links to individual structural technology
Links to individual functional technology
Links to individual associated computer programs
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