热塑性聚氨酯改性沥青流变性能及适宜掺量研究

Study on Rheological Properties and Appropriate Dosage of Thermoplastic Polyurethane Modified Asphalt

摘要:

为评价T30型热塑性聚氨酯（TPU）掺量对基质沥青性能的影响，采用针入度、软化点、延度、布氏旋转黏度、存储稳定性、多应力蠕变恢复（MSCR）和弯曲梁流变（BBR）试验，对T30掺量分别为0%~8%的改性沥青各项性能进行对比。结果表明：随着T30掺量的增加，改性沥青针入度下降，软化点、延度持续升高，说明T30能增强其高温抗流动能力；同一温度下各组样品的布氏旋转黏度随着T30掺量的增加而增大，表明高掺量T30会降低沥青的施工和易性；T30可提高各组样品的弹性恢复率并降低其不可恢复蠕变柔量，从而增强沥青的高温抗永久变形能力；各组样品的存储稳定性随着T30掺量的增加而变差，其中高掺量样品更易发生离析。综合改性沥青的高温性能、低温流变、施工性与存储稳定性，T30较适宜的掺量范围为4%～6%。

Abstract:

In order to evaluate the effect of T30 type thermoplastic polyurethane (TPU) content on the performance of matrix asphalt, the tests of penetration, softening point, ductility, Brinell rotational viscosity, storage stability, multi-stress creep recovery (MSCR), and bending beam rheometer (BBR) are conducted to compare the various properties of modified asphalt with T30 dosages ranging from 0% to 8%. The result shows that with the increase of T30 dosage, the penetration of modified asphalt decreases, while the softening point and ductility continue to rise, indicating that T30 can enhance its high-temperature anti-flow ability. At the same temperature, the Brinell rotational viscosity of each group of samples increases with the increase of T30 dosage, indicating that a high T30 dosage will reduce the workability of asphalt during construction. T30 can increase the elastic recovery rate of each group of samples and reduce their irreversible creep flexibility, thereby enhancing the high-temperature resistance to permanent deformation of asphalt. The storage stability of each group of samples deteriorates with the increase of T30 dosage, in which samples with high dosage are more prone to segregation. Considering the high-temperature performance, low-temperature rheology, workability and storage stability of modified asphalt comprehensively, the appropriate dosage range of T30 is 4% to 6%.