水泥混凝土路面沥青缓冲隔离层动能耗散机理研究

发布时间：2018-10-30 13:36

【摘要】：水泥混凝土路面虽然具有强度高、刚度大等优点,但在车轮冲击振动荷载以及自然因素作用下路面早期断板现象十分普遍。而在面层与基层之间增设沥青缓冲隔离层后,冲击振动荷载由面层通过具有一定柔性的沥青隔离层传递到基层,有效缓解了路面结构受到的冲击振动,可耗散掉路面板的振动能量。但目前对水泥混凝土路面沥青缓冲隔离层动能耗散性能研究甚少。本文着重对水泥混凝土路面沥青缓冲隔离层的动能耗散机理及在不同影响因素下的动能耗散效应进行研究。采用自行研发的落球试验装置,依据美国ACI544委员会提出的落球法对路面结构实施振动冲击,研究贫混凝土基层有、无沥青缓冲隔离层及不同影响因素下沥青缓冲隔离层路面结构振动响应。结果表明,路面板的振动作用是一个逐渐衰减的过程,并伴随着能量耗散；沥青缓冲隔离层能够有效地减小路面板的振动响应幅值,显著提高路面结构的动能耗散效果；空隙率较大时能降低振动响应幅值,提高缓冲能力；90#沥青较70#沥青更有利于削减冲击力；沥青缓冲隔离层掺加橡胶粉比普通沥青缓冲隔离层具有更为优异的减振耗能效果,橡胶粉掺量为15～20%较为适宜；隔离层厚度取3-4cm时,其动能耗散效应较为理想。采用电液伺服试验系统对不同路面结构进行模拟车轮荷载冲击振动作用的疲劳破坏试验,分析了路面结构动力响应与疲劳寿命的相关性。得知沥青缓冲隔离层起到良好的减振效果,削减了路面结构受到的冲击力,显著增加了路面结构的疲劳寿命；与70#沥青缓冲隔离层相比,90#沥青缓冲隔离层振动衰减速度更快,对路面板振动能量耗散程度更高,延长了路面结构的疲劳寿命；沥青缓冲隔离层在掺加橡胶粉后,路面结构的振动响应得到显著改善,使振动衰减更为迅速,极大地吸收车轮对路面板的冲击能量,大幅提升了使用寿命；随着沥青缓冲隔离层厚度的增加,基层受到的冲击力得到缓解,但不利于削弱车轮荷载对路面板产生冲击振动效应,路面结构的使用寿命仅略有增加。根据试验研究结果,建议沥青缓冲隔离层使用90#沥青,级配采用空隙率较大的配合比。
[Abstract]:Although cement concrete pavement has the advantages of high strength and high stiffness, it is very common to break the pavement slab in the early stage under the impact vibration load of wheel and natural factors. After adding the asphalt buffer isolation layer between the surface layer and the base course, the impact vibration load is transferred from the surface layer to the base course through the asphalt isolation layer with certain flexibility, which effectively alleviates the impact vibration of the pavement structure. The vibration energy of the road panel can be dissipated. However, there is little research on the kinetic energy dissipation performance of asphalt buffer isolation layer on cement concrete pavement. In this paper, the kinetic energy dissipation mechanism of asphalt buffer isolation layer on cement concrete pavement and the kinetic energy dissipation effect under different influence factors are studied. Based on the falling ball method proposed by the ACI544 Committee of the United States, the impact of vibration on the pavement structure was studied by using the self-developed drop test device, and the poor concrete base was studied. Vibration response of pavement structure without asphalt buffer isolation layer and different influencing factors. The results show that the vibration of the pavement slab is a process of gradual attenuation and accompanied by energy dissipation, and the asphalt buffer isolation layer can effectively reduce the vibration response amplitude of the pavement slab, and significantly improve the kinetic energy dissipation effect of the pavement structure. When the voidage ratio is larger, the vibration response amplitude can be reduced and the buffering capacity can be improved, 90# asphalt is better than 70# asphalt in reducing the impact force. The addition of rubber powder into asphalt buffer isolation layer is more effective than ordinary asphalt buffer isolation layer in reducing vibration and energy dissipation. The rubber powder content is 1520% and the kinetic energy dissipation effect is better when the thickness of the isolation layer is 3-4cm. An electro-hydraulic servo test system was used to simulate the fatigue failure of different pavement structures under wheel load shock vibration. The correlation between the dynamic response of pavement structure and fatigue life was analyzed. It is known that the asphalt buffer isolation layer plays a good damping effect, reduces the impact force of the pavement structure, and significantly increases the fatigue life of the pavement structure. Compared with 70# asphalt buffer isolation layer, the vibration attenuation speed of 90# asphalt buffer isolation layer is faster, and the vibration energy dissipation degree of road panel is higher, which prolongs the fatigue life of pavement structure. After adding rubber powder into asphalt buffer isolation layer, the vibration response of pavement structure is improved significantly, and the vibration attenuation is more rapid, which greatly absorbs the impact energy of the wheel to the road panel and greatly increases the service life. With the increase of the thickness of the asphalt buffer isolation layer, the impact force of the base is alleviated, but it is not conducive to weakening the impact vibration effect of the wheel load on the pavement slab, and the service life of the pavement structure is only slightly increased. According to the experimental results, it is suggested that 90# asphalt should be used in the asphalt buffer isolation layer and the mix proportion with large void ratio should be used in the gradation.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U416.216

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