Testing and Evaluation of Recovered Traction Sanding Material.

摘要

The Montana Department of Transportation (MDT) is searching for a solution to the accumulation of traction sand that is applied to Montana highways every winter. An analysis of reuse and recycle options for salvaged traction sand was conducted using results of mechanical and chemical tests conducted on samples collected along the Bozeman Pass and the Lookout Pass areas. The results indicate there are viable alternatives to landfilling or roadside dumping of collected traction sand. The most appealing and cost-effective option is to reuse the collected material as traction sand in subsequent winters. A potential secondary option would be to process and mix (co-mingle) collected sand with gravel to produce a material that meets MDT gradation specifications for imported aggregate. The most promising co-mingling options are those that only necessitate the addition of finer aggregate and do not require additional coarse particles. MDT materials including plant mix surfacing, cement treated base, shoulder gravel, and crushed top surfacing could be economically produced by co-mingling collected traction sand with additional aggregate. Based on laboratory tests conducted to measure chemical and metals concentrations, it appears that the samples tested in this study have chemical and metal concentrations that are generally characteristic of naturally occurring background levels. Nonetheless, a quality assurance process is recommended before reusing recovered traction sanding material to confirm that unhealthy levels of contaminants are not present. An implementation plan outlining best practices for separating, collecting, testing and processing salvaged traction sand is described. The results of this study indicate that the practice of recycling and reusing traction sand could potentially save money by eliminating landfill costs and by reducing the amount of new abrasives and aggregates that are purchased every year.