高温-荷载耦合作用下废旧叠层轮胎隔震垫劣化机理分析

Experimental Study on Mechanical Properties of Scrap Tire Rubber Pads Under High Temperature-Load Coupling

为探究高温-荷载耦合作用下废旧叠层轮胎隔震垫(STP)劣化损伤,选取几何尺寸为180 mm×180 mm×69 mm的6层STP,将其置于高温100℃、常温20℃,荷载4 MPa、5 MPa、6 MPa的耦合条件下进行308 h的温度侵蚀试验。随后进行扫描电镜(SEM)、拟静力加载试验,观察橡胶分子微观形态变化、STP外观变形以及轮胎炭黑移动过程,结合拟静力试验结果,综合阐明高温-荷载耦合作用下STP劣化机理。结果表明:高温-荷载耦合作用使STP橡胶表面层的交联密度显著提升、局部分子量增大、STP内部橡胶分子形成饱和化学键、反应活性降低、形态发生转变,导致STP竖向刚度在4 MPa下最大提高31.9%;水平等效刚度提高,但退化速率比常温下快;竖向变形性能变差,在不同设计压应力下的变形量均在2%以内;最大单圈耗能较常温下减小2.5%。研究成果可为新型墙下叠层隔震结构在高烈度村镇地区的推广和应用提供理论参考。

To study the degradation damage of the scrap tire rubber pads(STP)under the coupling action of high temperature and load,selected geo-metry size of 180 mm×180 mm×69 mm 6-layers of STP,placed it in high temperature of 100℃and the normal temperature 20℃,load of 4 MPa,5 MPa,6 MPa under the coupled condition of temperature erosion test of 308 h.Then,scanning electron microscope(SEM)and quasi static loading test,observed the micromorphological changes of rubber molecules,STP deformation process of carbon black and tires mobile appearance,combined with the pseudo-static test results,the mechanism of STP degradation under high temperature-load coupling was comprehensively elucidated.The results show that the coupling action of high temperature and load significantly increases the cross-linking density and local molecular weight of STP rubber surface layer,and the formation of saturated chemical bonds,reduced reactivity and morphological changes of rubber molecules inside STP leads to the maximum increase of the vertical stiffness of STP by 31.9%at 4 MPa.The horizontal equivalent stiffness is increased,but the degradation rate is faster than normal temperature.The vertical deformation performance ratio becomes worse,which is within 2%under different design compressive stresses,the maximum single-lap energy consumption is reduced by 2.5%compared with normal temperature.The research results can provide theoretical reference for the extension and application of new type of under-wall laminated isolation structures in high-intensity rural areas.