沥青混合料冲击疲劳特性试验研究

发布时间：2018-01-26 06:11

本文关键词： 沥青混合料力学响应疲劳冲击数值分析　出处：《重庆交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：沥青混凝土路面以其良好的路用性能得到广泛应用。当前,沥青混合料的高温稳定性、低温抗裂性能、水稳定性等都有成熟有效的、可用于研究或生产用的试验评价设备与方法。然而,对于沥青混合料的疲劳性能,虽然有UTM、MTS等试验设备,但这些试验设备较为昂贵,试验复杂、费时费力;从而造成当前沥青混合料的疲劳性能测试往往局限在大学、研究院等的科研活动研究中。同时,作为路面结构的行车荷载具有冲击特性;而当前对沥青混合料的疲劳特性很少从冲击荷载的角度进行分析和研究。基于以上现状,论文对沥青混合料的冲击疲劳试验设备、试验方法及疲劳特性进行研究。主要研究内容与结论如下:一、沥青混凝土路面在冲击荷载作用下的力学响应分析。①利用ANSYS三维有限元数值分析平台,建立了移动车辆荷载作用下沥青混凝土路面的数值模型,对车辆移动荷载作用下的路面力学响应规律进行分析。研究表明在车辆移动荷载作用下(速度),路面结构的路表计算点竖向应力在0.1s的时间内快速增加到0.898MPa,然后迅速在0.1s的时间内迅速下降到0Mpa。且随着深度的增加,呈快速降低趋势,到底基层顶时为路表的5.97%,到土基顶时已降到路表的0.75%,表明车辆荷载引起的路面结构的竖向应力变化符合冲击规律。②将车辆移动荷载分别简化为竖向荷载或者竖向与水平荷载;分别分析不同简化模式下的路面结构力学响应规律;结果表明,车辆水平移动荷载对路面结构竖向应力与竖向位移的影响较小;车辆水平移动荷载主要对路面结构的响应时程产生一定的影响;基于以上结论,论文将车辆移动荷载简化为移动恒定竖向荷载;③建立马歇尔自动击实仪的冲击荷载模型,分析了马歇尔自动击实冲击荷载对沥青混合料的作用规律;将车辆移动荷载与冲击荷载作用下的路面力学响应规律进行对比,发现二者规律一致,故可将车辆移动荷载采用马歇尔自动击实仪的冲击荷载代替。二、研发冲击疲劳试验机,并对沥青混合料试件进行高温稳定性、水稳定性及冲击疲劳等综合路用性能试验分析。①借鉴落锤式冲击疲劳试验机、SHPB冲击压杆装置,根据第一部分数值分析的结果,对马歇尔自动击实仪进行改装,制成冲击疲劳试验机;②对冲击疲劳试验机的加载方式、应变率比等参数进行试验研究,确定冲击疲劳试验参数及试验方法;③制备的沥青混合料试件,进行沥青混合料的综合路用性能试验。试验表明对应于沥青混合料的最大疲劳寿命存在着一个最佳的沥青用量,且该最佳沥青用量比当前规范规定的配合比设计中确定的最佳沥青用量大;随着沥青混合料最大公称粒径的增加,沥青混合料疲劳寿命缩短;对于相同最大公称粒径、不同粗细类型的沥青混合料,级配越细,疲劳寿命越长;同时,不同级配类型的沥青混合料,疲劳寿命相差较大,表现为SMA-13大于AC-13大于OGFC-13。
[Abstract]:The asphalt concrete pavement for its good pavement performance has been widely used. At present, the high temperature stability of asphalt mixture, low temperature crack resistance, water stability has a mature and effective, can be used for research or production of test equipment and methods. However, for the asphalt mixture fatigue performance of the material, although there are UTM. MTS test equipment, but the more expensive test equipment, test is complicated, time-consuming and laborious; resulting in the fatigue test of asphalt mixture is often limited in the University, Research Institute and other research activities. At the same time, as has the impact characteristic for traffic load pavement structure; and the fatigue properties of asphalt mixture from the angle of little impact load analysis and research. Based on the above situation, the impact of asphalt mixture fatigue test equipment, test method was studied and the fatigue properties. The main research The contents and conclusions are as follows: first, the mechanical response analysis of asphalt concrete pavement under impact load. Using ANSYS analysis platform of 3D finite element numerical model is established for asphalt concrete pavement under moving vehicle loads, the pavement subjected to moving vehicle loads response were analyzed. The results show that the vehicle moving loads under the table (speed), road pavement structure calculation of vertical stress in 0.1s period increased to 0.898MPa, and then quickly in the 0.1s period decreased rapidly to 0Mpa. and with the increasing depth, showed a rapid decrease in the end of 5.97%, the road surface is at the top, to the top of subgrade when the road surface has been reduced to 0.75%, showed that the vertical pavement traffic load induced stress changes in accordance with law. The impact of vehicles moving load are simplified as a vertical load or the vertical and horizontal load Load; pavement structure mechanics analysis respectively different simplified models of the response laws; the results show that the level of the vehicle moving loads on pavement structure should be vertical with the vertical displacement of the smaller impact force; the vehicle horizontal moving loads have a certain impact on the pavement response time history; based on the above conclusions, the vehicle load is simplified as mobile mobile constant vertical load; the establishment of Marshall compaction apparatus impact load model, analyzes the impact of Marshall compaction load on the asphalt mixture; pavement mechanics of vehicles moving load and impact load response of the comparison, it is found that the two laws are consistent, it can move the vehicle by impact load Marshall automatic load compaction device instead. Two, R & D impact fatigue testing machine, and the high temperature stability of asphalt mixture specimens, water stability and erosion Analysis on fatigue of integrated performance test. The reference impact fatigue testing machine, impact device SHPB pressure bar, according to the first part is the analysis of numerical results, modified Marshall compaction apparatus, made of impact fatigue testing machine; the impact fatigue testing machine load, strain rate ratio parameters experimental study to determine the impact fatigue test parameters and test method of asphalt mixture; the preparation of material specimens, comprehensive road asphalt mixture by performance test. The test shows that the maximum fatigue life of Yu Liqing mixture exists an optimum asphalt content, the optimum asphalt and the optimum asphalt content than with the current specification the ratio of design to determine in large amounts; with the increase of asphalt mixture maximum nominal size, shorten the fatigue life of asphalt mixture; for the same nominal maximum particle size, different thickness type The asphalt mixture, the finer the gradation, the longer the fatigue life. At the same time, the fatigue life of the asphalt mixture with different gradation types is quite different, showing that SMA-13 is greater than AC-13, greater than OGFC-13..

【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U414

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