Slip Resistance Using an Inclined-Plane Method

SLIP RESISTANCE USING AN INCLINED-PLANE METHOD 

As it is practically impossible to compare slip resistance or static coefficients of friction of various WPC materials using the same experimental approach (Table 11.3), I have undertaken—while preparing this book for the publication—a simplified comparison using the standard incline-plane method. This method is a standard experiment in mechanical physics and involves tilting a platform to the point where movement of a material first occurs. The tangent of the angle of the plane at the point of movement is equal to the static coefficient of friction. 

One can see that the values of static coefficient of friction are spread in a rather wide range. The three lowest values in the table are essentially for neat HDPE because the surface for unbrushed GeoDeck deck boards (not a commercial product) is practically a thin film of the plastic. Brushing increases the 

TABLE 11.5 Static coefficient of friction for piastic or WPC deck boards, measured using a simplified inclined plane method. All measurements were done in the most slippery directions, that is, along the grain. Date for dry and wet pressure treated lumber are given for a comparison 

Old GeoDeck (HDPE rice hulls)(not a commercial product after 2002) 0.39 

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