Evaluation of Thermoplastic Marking Materials

Due to the harsh conditions of airport environments, frequent repainting of existing waterborne pavement markings is required. This painting is expensive and affects life-cycle costs. A thermoplastic marking material has been identified as an alternative to the existing waterborne material. The purpose of this research effort was to determine if this thermoplastic marking material is as effective as the current waterborne material in terms of its retro-reflectivity, chromaticity, friction properties, and its adherence to the airport pavement surface.

Two types of thermoplastic materials were applied on asphalt and concrete surfaces at the Federal Aviation Administration William J. Hughes Technical Center and were evaluated for 1 year starting in June 2006. These materials were also applied on concrete pavement surfaces at the Newark Liberty International Airport and evaluated for 1 year starting in August 2006. One thermoplastic material was 60-mil thick with Type I and III beads and was applied on a heated surface; the other material was 90-mil thick with Type I and IV beads and was applied on cold surface. Retro-reflectivity was measured using a retro-reflectometer; a spectrophotometer was used to measure chromaticity, a Dyna-Meter Pull-Off tester was used to measure adherence strength, and a Saab Surface Friction Tester was used to measure friction properties. Most measurements were taken on a monthly basis. 

The results showed that the retro-reflectivity characteristics of thermoplastic marking materials were acceptable. The chromaticity of the thermoplastic was within tolerance for white, red, yellow, and black. The average friction readings recorded on thermoplastic were significantly lower than those taken on bare pavement and about 50% less than waterborne paint. The adherence showed that preparation is necessary for a good bond. The tensile strength of the bond between the thermoplastic marking material and hot-mix asphalt was acceptable. The tensile strength of the bond between the thermoplastic marking material and Portland cement concrete was acceptable when an additional adhesive was applied.

Based on the result of this evaluation, thermoplastic marking material is recommended for taxiways. 

DOT/FAA/AR-TN08/22
Authors: Holly Cyrus and Anthony J. Previti