开级配碎石透水基层集料颗粒微观接触劣化机制

Microscopic Contact Degradation Mechanism of Aggregate Particles of Open-graded Gravel Permeable Base

针对服役期开级配碎石透水基层集料颗粒微观接触劣化问题,研制了界面微观摩擦磨损劣化试验台,分析了界面微观摩擦磨损作用参数对集料颗粒接触界面微观劣化的影响规律,研究了服役期开级配碎石透水基层内部集料颗粒接触界面微观摩擦、磨损、界面构造水平及分布特性的演变规律。结果表明:集料颗粒接触界面微观劣化最佳试验参数为:10 N的法向接触荷载、5 Hz的相互作用频率和5 mm的相互作用位移幅值;水存在工况下玄武岩、石灰岩、花岗岩3种工程常见母岩材质的集料颗粒接触界面摩擦因数,均出现不同程度的降低现象,质地较软的石灰岩集料颗粒接触界面摩擦因数降低程度最大;集料颗粒接触界面磨损主要发生在颗粒摩擦接触初期阶段,水环境的存在一定程度上降低了集料颗粒接触界面磨损程度;磨屑造成的集料颗粒接触界面磨斑表面长波低频段和短波高频段的纹理构造水平低于集料颗粒自身晶粒构造造成的中波中频段纹理构造水平,水存在工况能够降低长波低频段和短波高频段的纹理构造,凸显集料颗粒自身晶粒构造造成的中波中频段纹理构造。研究成果有望为长寿命透水路面透水基层建设提供理论借鉴。

In order to solve the problem of micro contact deterioration of aggregate particles in open-graded crushed stone permeable base layer during service period,this study developed the interface micro friction and abrasion deterioration test bench,analyzed the influence of interface micro friction and abrasion parameters on the micro deterioration of the contact interface of aggregate particles,and researched the evolution of the micro friction and abrasion of the contact interface of aggregate particles,and the level and distribution characteristics of the interface in the open-graded crushed stone permeable base layer during service period.The results show that:the best test parameters for the micro-degradation of aggregate particle contact interface are:10 N normal contact load,5 Hz interaction frequency and 5 mm interaction displacement amplitude;the friction coefficients of the aggregate particle contact interface of basalt,limestone and granite,three kinds of common parent rock materials,under the condition of water presence,are reduced to different degrees,and the friction coefficient of the contact interface of the aggregate particles from the softer limestone has been reduced the most;the friction coefficient of the contact interface of aggregate particles from the softer limestone has been reduced the most.The friction coefficient of the aggregate particle contact interface is reduced to the largest extent;the wear of the aggregate particle contact interface mainly occurs in the early stage of particle friction contact,and the existence of water environment reduces the degree of the wear of the aggregate particle contact interface to a certain extent;the texture structure level of long-wave low-frequency band and short-wave high-frequency band on the surface of abrasive spots caused by abrasive debris at the contact interface of aggregate particles is lower than that of medium-wave middle-frequency band caused by the grain structure of aggregate particles,and the presence of water can reduce the texture structure of long-wave low-frequency band and short-wave high-frequency band,and emphasize the medium-wave middle-frequency band caused by the grain structure of aggregate particles themselves.The research results presented here are expected to provide theoretical reference for the construction of permeable base layer of long-life permeable pavement.