The effect of surface roughness on the measurement of slip resistance

Friction coefficient is widely used to measure slipperiness. It is also kno wn that surface roughness affects friction. Surface roughness on quarry til es was systematically varied by sand blasting. The relationship among slip resistance, tile surface roughness, surface conditions and slipmeters used was investigated. The results indicated that the effect of surface roughnes s on friction index depends on the slipmeter used, due to the different cha racteristics among these slipmeters. It was also shown that tile surface ro ughness could be correlated with the measured friction index. For dry surfa ces, surface parameters R-a and R-3z (see Table 1 for definitions) had the highest correlation with the measured friction indices among 21 surface par ameters evaluated in the study. Surface parameters R-pk and R-pm had the hi ghest correlation with the measured friction indices for wet surfaces. A ro ugher surface generally led to a higher friction index. For wet surfaces, m oreover, sharper and higher peaks with an optimal high peak density on tile surfaces could increase friction index further.