基于蠕变试验计算沥青的低温松弛弹性模量

Calculation of Low-Temperature Relaxed Modulus of Elasticity for Bitumen via Creep Test

为了利用易操作的试验得到沥青的低温松弛弹性模量,采用沥青弯曲梁流变仪(BBR)测得沥青的蠕变柔量,通过对蠕变试验数据在时域内进行离散,根据蠕变与松弛之间的本构关系建立松弛弹性模量和蠕变柔量的数值迭代表达式.从迭代表达式可以计算出沥青在基准温度下的松弛弹性模量.使用时温等效换算法则可以得到不同温度下的松弛弹性模量主曲线,分析松弛弹性模量主曲线特性可以评价沥青的低温性能,为工程上选择合适的沥青提供参考.

In order to obtain the low-temperature relaxed modulus of elasticity for bitumen by tests with easy manipulation, the blending beam rheometer （BBR） was used to measure the creep compliance. The experimental data of BBR were then discretized in time domain. According to the constitutive relationship between the creep and the relaxation, a numerical iteration expression was thus proposed to describe the relationship between the relaxed modu- lus of elasticity and the creep compliance. By the proposed expression, the relaxed modulus of elasticity for bitumen at the fiducial temperature was further calculated. Moreover, the main curves of the relaxed modulus of elasticity at different temperatures were drawn via the time-temperature equivalent principle. The characteristics of the main curve were finally analyzed and were used to evaluate the low-temperature performance of bitumen, thus providing some references for making the right choice of bitumen in practical engineering.