基于DSR的改性沥青及混合料动态黏弹性能

Dynamic viscoelastic properties of modified asphalt and mixture based on DSR

为了在相似加载条件下比较改性沥青及混合料的动态黏弹性能,选择4种不同特点的改性沥青,成型了混合料小梁试件.应用动态剪切流变仪(DSR)分别进行了不同温度下的频率扫描试验,根据时间-温度等效原理构建了改性沥青及混合料的流变主曲线,对主曲线形态和流变模型拟合结果进行了对比分析.研究表明:改性沥青及混合料的复数剪切模量主曲线形态相似,采用改进型CAM模型进行拟合的效果很好,相关系数在0.996以上;平衡复数剪切模量G*e可用来区分不同类型改性沥青及其混合料的高温性能;高强改性沥青的高温抗车辙性能明显优于其他改性沥青,但软化点和60℃动力黏度不适用于评价高强改性沥青.改性沥青的动态力学响应能够反映其混合料的黏弹性能.

In order to compare the dynamic viscoelastic properties of modified asphalts and mixtures at similar loading conditions,four kinds of modified asphalts with different characteristics are select-ed,and the beam specimens of their mixtures are formed.Frequency sweep tests at different temper-atures are conducted by a dynamic shear rheometer （DSR）.The rheological master curves of modi-fied asphalts and mixtures are constructed by the time-temperature superposition principle,and the shapes of master curves and fitting results are analyzed comparatively.The results show that the complex shear modulus master curves of modified asphalts and mixtures,which have similar shapes, can be fitted well by the improved CAM model with correlation coefficients above 0.996.The equi-librium complex shear modulus,G＊e ,can identify the high-temperature properties of different kinds of modified asphalts and mixtures.The rutting-resistance of high-strength modified asphalt at high temperatures is vastly superior to that of other modified asphalts,but softening point and dynamic viscosity at 60 ℃ are not suitable to evaluate it.The dynamic mechanical responses of modified as-phalts can reflect the viscoelastic properties of their mixtures.