应用自洽方法预测沥青混合料的蠕变行为

Prediction of relaxation modulus of asphalt mixture with self-consistent method

将沥青混合料看作是由沥青砂和粗骨料组成的两相复合材料,提出了应用自洽方法预测沥青混合料粘弹性性能的一般思路。采用四参量流变模型描述沥青砂的粘弹性能,通过Laplace变换将时间域的粘弹性问题转化为变换域的线弹性问题,然后经Laplace逆变换将变换域的解转化到时间域。利用不同温度、不同应力水平下沥青砂的单轴压缩蠕变实验,拟合四参量流变模型参数,预测了沥青混合料在不同温度和不同应力水平下的蠕变曲线,并与实验结果进行了比较,发现蠕变的早期阶段预测值与实验值基本符合。最后进一步分析了温度、应力水平对沥青混合料蠕变行为的影响。

Treating asphalt mixture as a two-phase composite material composed of asphalt mastic and coarse aggregates,a prediction method for viscoelastic properties of asphalt mixture with the self-consistent method is proposed.With the viscoelastic behavior of asphalt mastic described by the four-parameter model,the viscoelastic problem in the time domain is linearized in the transformed domain through the Laplace transformation,and then the solution in the transformed domain is transferred into the time domain through the inverse Laplace transformation.After the parameters in the four-parameter model of asphalt sand are obtained by fitting the uniaxial creep experiments under different loading stresses and temperatures,the creep curves of asphalt mixture under different stresses and temperatures are predicted and compared with the experimental results.Good agreement is observed between the predicted and experimental results within a short period of time.Then the effects of the temperature and the loading stress on the creep behavior of asphalt mixture are discussed.