PRELIMINARY-STUDY OF THE EFFECT OF FINES ON SANDED-ICE FRICTION

Small-scale laboratory tests were performed on sanded ice. Four standard sands, as specified by various regulatory agencies, were tested. Sliding friction was measured for a rubber-faced slider for each sand type at a temperature of -10-degrees-C on three prepared surfaces: bare ice, loose sanded ice and ice with sand frozen on. We found friction coefficients for bare ice to be higher than those measured on loosely sanded ice and, in some cases, on ice with sand frozen on. Test results, presented as a performance ratio (ratio of coefficients for sanded ice to bare ice), allowed a distinct ranking of the sands' effectiveness. Performance ratios for frozen-on sand were significantly greater than for loose sand for a given sand type. The performance ratio showed a strong, linearly increasing trend as the percentage of a given fine grain size in the sand was increased. We found that this line had a steeper slope for the percentage of material smaller than 0.177 mm as compared with that smaller than 0.297 mm. Also, there were greater increases in traction with increases in fines for frozen-on sand as compared with loosely sanded ice.