Flamespray Coating as an Environmentally Acceptable Pavement Marking Technique
[ NCHRP 20-30 (NCHRP-IDEA) ]
Project Data
Staff Responsibility:
Dr. Inam Jawed
This project was aimed at developing an environmentally safe flamespray coating technique using new polymer formulations for pavement marking. Initial investigations of commercially available alkyd thermoplastic resins suggested their suitability for flamespray applications. However, the resins contained premixed glass beads that made them unsuitable for flame spray applications. Also, the resin particle size was found to be was too large to allow a uniform flame spraying. These problems were addressed by custom blending the alkyd resin without glass beads, melt extruding and cryogenic grinding to reduce particle size. However, the process produced very fine dust-like particles and the non-resin components in the mix tended to separate when the material was fluidized. Two new formulations with different levels of solid plasticizer in base resin were compounded via extrusion followed by cryogenic grinding to reduce the particle size of the product. These formulations could be flamesprayed onto concrete substrates and showed good adhesion and abrasion resistance. The approach appears feasible but will require modification of the spray gun to obtain better edge definition. Also, the glass beads will have to used as a “drop on” application immediately following the resin spraying. Further work is necessary to optimize the resin formulations and evaluating their long-term weather durability. The final report is available from the National Technical Information Service (NTIS # PB2003-102865).
