What is a common tool used to measure asphalt thickness?

A nuclear density gauge is widely recognized as a common tool used in the asphalt paving industry to measure asphalt thickness. This tool utilizes radioactive isotopes to assess the density of the asphalt layer, providing a direct correlation to its thickness. The gauge emits gamma rays that penetrate the asphalt; the amount of radiation that is returned to the sensor is used to determine both density and thickness.

This method is advantageous because it allows for quick, non-destructive measurements, enabling asphalt quality to be assessed on-site during construction. In addition, the nuclear density gauge provides reliable data, which is essential for ensuring that the pavement meets specified thickness requirements necessary for performance and longevity.

Other options, while they can be used in some contexts, do not match the effectiveness and specificity of a nuclear density gauge for measuring asphalt thickness. A steel ruler may provide a basic measurement but lacks the precision and ability to assess density. A laser measure could offer distance measurements but isn't specifically designed for asphalt thickness. An ultrasonic thickness gauge might be suitable for other materials but is not as commonly used or as effective in asphalt applications.