Wax Build-Up on the Surfaces of Natural Rubber Bridge Bearings

摘要

The problem of excessive slip and walking of natural rubber bridge bearing padswas investigated as part of the overall research project 0-1304, Elastomeric Bridge Bearings. One of the principal factors related to this phenomena was the waxy residue found on the bearing pads and their contact concrete surfaces from problem bridges. Spectroanalysis established that the surface material on the natural rubber bearings taken from two Texas bridges was paraffin wax. This wax is added primarily to permit the natural rubber elastomer to pass the ASTM test on resistance to ozone attack. An examination of the literature indicated that the ASTM tests required by AASHTO are neither accurate in assessing true behavior in the full-size bearing nor relevant to the bearing's performance in practice so that the wax additive may not be necessary.