剪切工艺条件对SBS改性沥青性质的影响

考察了剪切频率、剪切时间和发育时间对SBS改性沥青软化点、25 ℃针入度、5 ℃延度、PI值的影响。结果表明，剪切时间与剪切速率对提高软化点有一定的互补作用，增加剪切时间与剪切速率在促进SBS颗粒空间三维网状结构形成、提高软化点的同时，限制了其低温塑性变形（5 ℃延度），降低了PI值；发育时间对SBS改性沥青性能影响相对较小。工艺参数对25 ℃针入度的影响相对较小。确定SBS改性沥青的最佳工艺条件为：剪切时间90 min,发育时间30 min ,剪切速率4 000 r/min。该条件下制备的改性沥青能够满足SBS类(I-C)的技术要求，同时提出可以通过调整某个工艺参数，有针对性地改善改性沥青某一方面的性质。

EFFECT OF SHEARING PROCESS CONDITIONS ON THE PROPERTIES OF SBS-MODIFIED ASPHALT

The effects of shearing frequency, shearing time and development time on the softening point, 25℃ penetration, 5℃ductility and PI value of SBS-modified asphalt were investigated. It was found that the function of shearing frequency and shearing time was complementary someway in improving the softening point of asphalt, yet such improvement caused by the formation of SBS network could limit its ductile deformation (5℃ductility) and reduce its PI value. The development time had less influence on the performance of modified asphalt, as well as the process parameters had relatively less influence on the 25℃ penetration. The qualities of modified asphalt prepared under the optimum conditions of a shearing time of 90 min, a shearing frequency of 4 000 r/min and a development time of 30 min well met the requirements of the specifications for SBS (I-C) asphalt. Furthermore, it was also proposed that some performance of modified asphalt could be improved by adjusting certain process parameters.