基于新型蠕变试验仪的沥青蠕变性能研究

发布时间：2018-11-25 07:19

【摘要】：随着我国交通事业的发展,对路面材料研究的逐步深入,重视沥青与沥青混合料的粘弹性行为及路用性能已经成为了研究沥青路面的一个趋势。本文采用大连理工大学道路教研室自主开发的沥青旋转剪切蠕变试验仪,对不同种类沥青的蠕变性能进行了分析与评价,旨在为沥青粘弹性力学行为的研究与应用提供一种新的方法与手段,促进粘弹性理论及其试验设备与方法在沥青路面试验测试中的应用。 本文首先介绍了沥青旋转剪切蠕变试验仪的工作原理与试验方法,选取了6种具有代表性的沥青并对其进行了基础试验。 第二,采用蠕变试验仪研究了不同种类沥青、温度及应力水平对沥青单次蠕变的蠕变应变、蠕变回复率、蠕变劲度等蠕变指标的影响规律。研究结果表明,同一应力水平下沥青的蠕变应变随温度上升而增大,且增大的幅度越来越大,蠕变回复率和蠕变劲度随着温度升高不断减小；20℃较低应力水平下,应力水平对蠕变劲度的影响很小,多数沥青的蠕变回复率随着应力水平的增加逐渐减小；幂函数S(t)=Bt(-m)能够很好的表征沥青蠕变劲度与时间的关系；标号不同的基质沥青之间蠕变性能差别很大,改性剂的添加可以有效减小沥青的总变形,并且提高变形中的弹性变形的比例,老化过程可以很大程度的改变沥青的蠕变性能,再生剂的添加可以增加老化沥青中的粘性成分,恢复沥青的粘弹性性质。 第三,采用蠕变试验仪研究了沥青种类、应力水平和蠕变次数对沥青重复蠕变回复性能的影响。研究结果表明,20℃时,不同种类沥青的蠕变回复率相差很大,基质沥青和再生沥青的蠕变回复率都比较小,改性沥青和老化沥青的蠕变回复率比较大；重复蠕变回复试验更能区分改性沥青的粘弹性性质；20℃较低应力水平下,蠕变回复率会随着荷载作用次数的增加逐渐增加,并趋向稳定,单次最大剪应变随着荷载作用次数的增加不断减小,并逐渐趋向稳定。 最后,采用低温弯曲梁流变仪(BBR)试验对不同种类沥青的低温蠕变性能进行了研究,结果表明：老化过程增加了沥青的低温蠕变劲度,并且减小了沥青的劲度变化率,从而降低了沥青的低温性能；而再生过程能够有效地降低沥青的低温劲度,增加沥青的劲度变化率；改性沥青能够有效降低沥青的低温蠕变劲度,但是同时也减小了沥青的劲度变化率,对于改性沥青应该结合其他试验来评价其低温性能；Burgers模型可以有效地描述基质沥青、改性沥青、老化沥青和再生沥青的粘弹性,进一步证明了采用Burgers模型拟合沥青材料的合理性。
[Abstract]:With the development of transportation industry in China, the research on pavement materials has been deepened step by step. It has become a trend to pay attention to the viscoelastic behavior and road performance of asphalt and asphalt mixture. In this paper, the creep properties of different kinds of asphalt are analyzed and evaluated by using the rotary shear creep tester developed by the road teaching and research department of Dalian University of Technology. The purpose of this paper is to provide a new method and means for the study and application of viscoelastic behavior of asphalt, and to promote the application of viscoelastic theory and its testing equipment and method in asphalt pavement test. In this paper, the working principle and test method of asphalt rotary shear creep tester are introduced. Six kinds of representative asphalt are selected and the basic tests are carried out. Secondly, the effects of different asphalt, temperature and stress levels on creep strain, creep recovery rate and creep stiffness of asphalt were studied by using creep tester. The results show that the creep strain of asphalt increases with the increase of temperature, and the creep recovery rate and creep stiffness decrease with the increase of temperature. At the low stress level of 20 鈩，

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