Use of Abrasives

Sand and other abrasives are used to provide temporary traction improvement at slippery spots when pavement temperatures drop below the effective range of regular deicing chemicals (e.g. <-7C).  Abrasives do not melt snow and ice and are only effective when they stay on top of ice or packed snow.  The following is a list of some general findings from literature on the effect and limitations of abrasives such as sands for winter road maintenance:  
  • Sand has exhibited limited effectiveness at higher vehicle speeds, especially when it is not been prewetted. Mixing sand with salt to keep it from freezing also limits sand’s effectiveness.
  • Studies suggest that at highway speeds sand is swept off the road after relatively few vehicle passes (eight to 12) and that friction gains from sanding (when the sand remains on the road) are minimal.
  • Friction improvement with sands for snow- and ice-covered roadways is quite small.
  • During storm periods when anti-icing operations are successful, abrasive applications provide no consistent or apparent benefit in hard-braking friction, traction or pavement condition. 
  • A mix of abrasives and chemical will usually be no more effective as an anti-icing treatment during snowstorms than the same amount of chemical placed alone. 
  • Some study has also indicated that the melting of snow and ice will be delayed by using a mixture of salt and sand. That is, in a blend, sand and salt may work against each other. The salt in the mix may blow away as vehicles travel the roadway. If the sand remains on snow, tires can push the sand down into the slush, making it ineffective for improving traction. 
  • Use of salt/abrasives mixes at moderately or much higher application rates than straight chemical does not lead to corresponding improvements in hard-braking friction or pavement conditions. 

Because both traffic and speed at parking lots and sidewalks are usually quite low, it is expected that abrasives could be effective in providing temporary friction enhancement, especially when the temperature is below the effective range of rock salts.