Water Resistance of Polyurethane Modified Epoxy Resin
Polyurethane modified epoxy resin has good bonding performance and deformation resistance,and has become one of the choices of bonding layer materials for steel bridge deck pavement.Based on the solid project of steel bridge deck in a coastal area of Shandong Province,the water damage resistance of polyurethane modified epoxy resin as the bonding layer of steel bridge deck was studied.The dry-wet cycle and freeze-thaw cycle tests of water erosion were designed.The mechanical properties and microscopic damage mechanism after water action were studied by combining macro and micro test methods.The results are as follows.During the dry-wet/freeze-thaw cycles,the appearance color of the polyurethane modified epoxy resin becomes yellow,and the internal defects cause stress concentration,resulting in a decrease in tensile strength and elongation at break.With the increase of the number of dry-wet/freeze-thaw cycles,the shear strength between the resin and the steel plate decreased in the early stage,and increased slightly in the later stage,and the overall change was not significant.Under the action of water,the ester group has a certain hydrolysis,the water contact angle is re-duced,the hydrophilicity is enhanced,and the crazing or crack propagation damage can be found under the mi-croscopic tensile fracture surface.
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