老化及海蚀作用下近海桥梁隔震支座橡胶材料性能劣化试验

Experimental research on property deterioration of rubber material used as natural rubber isolator for offshore bridges under aging and marine corrosion

设计了由与橡胶隔震支座相同材料的橡胶片组成的橡胶块体,将橡胶支座与橡胶块体和橡胶片放置在同样的试验环境下开展试验,研究橡胶材料硬度、定伸应力、拉伸强度及扯断伸长率在老化和海蚀作用下随时间及厚度方向的变化规律。试验结果表明:老化仍然是影响橡胶材料性能的主要因素;橡胶含水率的高低会极大影响其性能;随老化时间的增长,橡胶的硬度、定伸应力呈增大的趋势,而拉伸强度、扯断伸长率呈减小的趋势;单纯海蚀对橡胶硬度、定伸应力的影响不明显,但拉伸强度和扯断伸长率则随着海蚀时间的增长而减小;老化+海蚀试验结果是老化作用与海蚀作用的叠加,该作用会使得橡胶的性能劣化在大应变时表现得更为明显;从橡胶表面至内部,橡胶材料性能大体呈略微减小的趋势,老化及海蚀作用基本发生在表面,而内部橡胶的性能变化程度均较轻。

Rubber block and rubber sheet were designed and put in the same test environment as the natural rubber isolator.Rubber properties,such as hardness,stress in definite strain,tensile strength and elongation at break,under pure aging,pure marine corrosion,and the combination of aging and marine corrosion were studied.The corresponding change rules were given.The test results indicate that aging is the main factor influencing natural rubber property.Water ratio of rubber can greatly affect its performance.With aging time increasing,hardness and stress at definite strain of the rubber increased,but tensile strength and elongation at break decreased.The influence of pure marine corrosion on hardness and stress at definite strain is not obvious,but tensile strength and elongation at break is reduced with marine time.Under the combined action of aging and marine corrosion,property deterioration of the natural rubber is more serious,especially when the rubber is with large strain.From the surface to the inner of the rubber block,rubber property parameters slightly decrease.Property deterioration generally occurs in the rubber surface.The property of the inner rubber rarely changes.