Deterioration of Green Conflict Paint for Bicycle Facilities

Bicyclists depend on the visibility of the surrounding environment to maintain a safe travel path. Throughout the country, new types of bicycle infrastructure and pavement markings are being installed. This study used a new procedure to evaluate different pavement markings used in bike lanes. Three different paints were evaluated, including green waterborne paint, green liquid methacrylate paint, and white thermoplastic paint. The deterioration of these materials was tested under different conditions to simulate wear from motorized vehicles and street equipment. Surface polishing (i.e., repeated passing over the material) was examined under pneumatic tires, steel wheels, and steel scraper blades. Different characteristics were measured, including durability, retroreflectivity, color changes, and friction of the test materials. The results demonstrated that the procedure used in this study was able to evaluate different materials in a shorter time than field evaluation, which often can take years to complete. As expected, = retroreflectivity decreased with the number of polishing cycles. Overall, there was a significant decrease in percentage of retroreflectivity after 1,000 cycles for all testing conditions before retroreflectivity reached a terminal value. These results were consistent with field observations. A logarithmic model was found to describe the change in the retroreflectivity versus the number of loading cycles with high R2-values. The methacrylate paint experienced the lowest color loss, even after 100,000 cycles, irrespective of the exposure and the testing conditions. It is believed that the small reduction in color was due to the presence of chemicals coupled with the thicker paint of the methacrylate materials in comparison to the thickness of the waterborne materials. The durability results demonstrated that the waterborne markings peeled off the surface with increasing numbers of polishing cycles.US Department of Transportation Pacific Northwest Transportation Consortium University of Idah