Sealing is at the origin of rubber slipping on wet roads.
Loss of braking power and rubber skidding on a wet road is still an open physics problem, as neither the hydrodynamic effects nor the loss of surface adhesion that are sometimes blamed really manage to explain the 20-30% observed loss of low-speed tyre-road friction. Here we report a novel mechanism based on sealing of water-filled substrate pools by the rubber. The sealed-in water effectively smoothens the substrate, thus reducing the viscoelastic dissipation in bulk rubber induced by surface asperities-well established as a major friction contribution. Starting with the measured spectrum of asperities one can calculate the water-smoothened spectrum and from that the predicted friction reduction, which is of the correct magnitude. The theory is directly supported by fresh tyre-asphalt friction data.
Persson
B N J
BN
IFF, FZ-Jülich, 52425 Jülich, Germany.
Tartaglino
U
U
Albohr
O
O
Tosatti
E
E
D000063:Accidents, Traffic; D003198:Computer Simulation; D004548:Elasticity; D017276:Friction; D006244:Hardness; D006838:Hydrocarbons / Q000737:chemistry*; D008422:Materials Testing / Q000379:methods*; D008956:Models, Chemical; D012212:Rheology / Q000379:methods*; D013499:Surface Properties; D014783:Viscosity; D014867:Water / Q000737:chemistry*
D006838:Hydrocarbons; D014867:Water; C006647:asphalt