基于一种新型蠕变试验仪的沥青蠕变性能

Creep Properties of Asphalt Based on a New Creep Test Device

目的研究温度和应力水平对不同种类沥青蠕变性能的影响规律,促进黏弹性理论及其试验设备与方法在沥青试验测试中的应用.方法利用一种新型蠕变试验仪研究温度和应力水平对5种沥青蠕变总应变、蠕变回复率和蠕变劲度的影响.结果相同应力水平下,随着温度的升高5种沥青的蠕变总应变不断增大,蠕变回复率逐渐减小,蠕变劲度不断减小;20℃较低应力水平下,蠕变总应变与应力水平近似成直线关系,多数沥青的蠕变回复率随着应力水平的增加不断减小,各应力水平下的蠕变劲度曲线基本相同.结论添加SBS和橡胶粉改性剂可以有效减小沥青的总应变,并且提高弹性变形的比例,老化过程可以很大程度的改变沥青的蠕变性能,添加再生剂可以恢复沥青的黏弹性质;在双对数坐标轴下,5种沥青的蠕变劲度与时间具有比较好的线性关系,幂函数能够很好地表征沥青蠕变劲度与时间的关系.

The purpose of this paper is to understand influence of temperature and stress level on creep properties of different asphalt types and to make promotion on application of visco-elastic theory as well as device and method in asphalt tests. Using a new developed creep test device, the influences of temperature and stress level on total strain, creep recovery and creep stiffness of five asphalt binders are studied. Results show that under the same stress level, the total creep strain of five asphalt mixtures increases with increase of temperature, while the creep recovery rate and creep stiffness decrease. At 20℃ and under the low stress status, the total strain shows a linear relationship with stress level. In most cases, the creep recovery rate decreases as the stress level increases. Creep stiffness curves are basically same under different stress levels. Conclusion is that using of SBS and rubber powder modifier can effectively reduce the total strain of asphalt as well as in- crease the proportion of elastic deformation. Aging process can largely change the creep properties of asphalt. Adding regenerant can restore the viscoelasticity of asphalt. In the double logarithmic axes,the creep stiffness of each asphalt binder has a good linear relationship with time and the power function can characterize this relationship accurately.