We measure the displacement response of a frictional multicontact interface between identical polymer glasses to a biased shear force oscillation. We evidence the existence, for maximum forces close below the nominal static threshold, of a jamming creep regime governed by an aging-rejuvenation competition acting within the micrometer-sized contacting asperities. The time dependence of the creep process deviates from the standard Rice-Ruina [J. R. Rice and A. L. Ruina, J. Appl. Mech. 50, 343 (1983)] phenomenology at early times; this suggests the possibility of an aging-rejuvenation competition at much smaller scales, within the nanometer-thick adhesive junctions.
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