4mm DSR试验与BBR试验评价沥青低温流变性能比较研究

Rheological Testing of Asphalts at Low Temperatures with 4 mm DSR and BBR

为更便捷、使用更少沥青样品来评价沥青低温流变性能,美国提出了使用DSR动态剪切流变仪和4mm(或8mm)平行板夹具的新的试验方法,称为4mm DSR试验。为验证该方法的有效性,基于4mm DSR试验方法并采用8mm平行板,评价不同种类沥青的低温流变性能,同时采用BBR试验进行比较。结果表明4mm DSR试验数据与BBR试验有较强线性相关性,且试验结果离散性更小,可以作为低温性能评价的补充试验。试验结果说明,30#沥青低温性能有限,而50#沥青的低温流变性能与70#及SBS改性沥青接近。

The low temperature rheological properties of different types of asphalts were investigated using 4 mm DSR method. And low temperature performance measurements were also carried out with a bending beam rheometer(BBR), a typical test in PG grade of SHRP. Results show that 4 mm DSR can be used at low temperatures for asphalts and the PG grades provided are almost the same as BBR. There are strong linear correlations between relaxation modulus measured by 4 mm DSR and creep stiffness by BBR, and also between relaxation rate(mr-value) and creep rate(mc-value). And the discreteness of data of 4 mm DSR test is smaller than that of BBR, thus the 4 mm DSR test is more reliable than BBR test.