BBR试验的沥青低温性能及粘弹性分析

Analysis of asphalt low temperature performance and viscoelasticity based on BBR test

采用低温小梁弯曲试验(BBR)对6种不同种类的沥青低温性能进行评价,利用时间温度等效原理获得了沥青的低温劲度模量主曲线,通过Burgers模型方程对BBR蠕变劲度曲线及其劲度模量主曲线进行拟合.结果表明:沥青的劲度模量衰减速度依赖于温度,温度越高、低温性能越好,劲度模量衰减速度越快,且在蠕变的起始阶段衰减最迅速;Burgers模型方程对BBR蠕变劲度曲线及劲度主曲线均具有较高的拟合程度;蠕变劲度曲线及劲度主曲线在拟合时首尾两端相对误差较大,中间段相对误差小,同时BBR试验劲度度曲线的拟合相对误差明显小于模量主曲线的相对误差.

This paper evaluated 6 kinds of asphalt low temperature performance by using BBR test and obtained the low temperature strength modulus master curve of asphalt according time--temperature equivalence principle. The result shows that asphalt stiffness modulus decay rate depends on the temperature, and when the temperature is higher, the low temperature performance is better and the stiffness modulus decay faster. At the same time, in the initial stage of creep the decay is the fastest. The Burgers model equations were fitted to the BBR creep stiffness curve and stiffness modulus master curve, and the result show that the fitting degree of model equations of Burgers to BBR creep stiffness curve and main stiffness curve fitted with Burgers model equations have high correlation coefficient; Creep stiffness curve and main stiffness curve both in fitting at the two ends has larger relative error, and the middle has smaller relative error. The relative error of BBR test stiffness curve is significantly less than that of the modulus master curve in fitting.