Methodology and device in measuring thickness of thermo-plastic tape in real time

摘要

Thermo-plastic tape (TPT) provides delineation on highways around the world. The thickness of TPT on pavement is a very important parameter to control the quality of TPT, calculate durability of TPT, and provide information for the maintenance and replacement of TPT. Traditionally, the thickness measurement is conducted by using pre-embedded plates and measuring the thickness of TPT after spraying of the TPT marking materials. This method is labor intensive and cannot obtain a continuous-thickness profile. Developing an automatic thickness measurement system for TPT marking materials is critical to pavement management and public safety. The measurement system developed in this paper uses laser triangulation technique to detect the thickness of TPT. A dedicated digital laser signal processing circuit is developed to restore thickness information. The thickness measurement system provides continuous real-time thickness measurement of TPT. Lab and field tests under various conditions with TPT marking materials on real pavement surfaces were conducted. The test results showed that the measurement system is capable of reaching the resolution of 5 mils on pavement. The developed system for thickness measurement of TPT has a 267 KHz working frequency, which is the highest among similar devices. The high speed allows the system to provide higher accuracy and more flexibility in various applications.