Friction Coefficient of Recycled Rubber Soles

The present work studies the possibility of using recycled rubber in soles. Different sizes of recycled rubber particles were bonded together and adhered to wooden block. Two types of test specimens of smooth and treaded surfaces were investigated. The tested rubber slid against ceramic surface, where coefficient of friction was determined. At dry sliding; results showed that coefficient of friction of treaded rubber recorded slight decreasing trend with increasing normal load. For smooth test specimens, friction coefficient showed remarkable increase followed by slight decrease with increasing rubber particle size. When the water covered the sliding surface, friction coefficient showed decreasing trend to minimum then significantly increased as the rubber particle size increased. In this condition, the spaces and gaps between the rubber particles and ceramic surface were big enough to allow the water to go out the contact area causing the friction to increase due to the increase of the partial rubber/ceramic contact. Besides, relatively smaller particles facilitated the water to be formed on the surface area, where friction coefficient decreased. It is proposed to use treaded rubber in water wet floor tiles.The same trend was noticed at detergent wet surfaces, where coefficient of friction displayed lower values than that regarded by sliding on water wet ceramic surface. Treaded rubber showed relatively lower friction than smooth one. The lowest friction values were displayed by smooth surface at oil sliding, where friction coefficient increased when rubber particle size increased.