基于MSCR试验的SBS改性沥青高温性能评价与分级

High Temperature Performance Evaluation and Grading of SBS Modified Asphalt Based on Multiple Stress Creep Recovery Test

采用多应力蠕变回复(MSCR)试验分别对不同SBS掺量(质量分数)的线型、星型SBS改性沥青在64,70℃下的不可回复蠕变柔量、蠕变回复率及其相应的应力敏感性进行了分析,依据AASHTO MP 19-10标准对不同SBS掺量的改性沥青进行高温性能分级.结果表明:随着SBS掺量的提高,改性沥青不可回复蠕变柔量呈减小趋势,蠕变回复率呈增大趋势,且当SBS掺量较低时,上述2种变化趋势更明显,即SBS掺量较低时,提高SBS掺量对改性沥青高温性能改善更为显著.SBS改性沥青不可回复蠕变柔量和蠕变回复率应力敏感性随SBS掺量的变化无明显规律可循.温度升高,SBS改性沥青不可回复蠕变柔量和蠕变回复率应力敏感性基本增大.以70℃作为SBS改性沥青高温性能分级的基准温度,可使各SBS掺量下改性沥青的高温性能区分更为明显.

Linear and radial styrene-butadiene-styrene mass） of SBS were characterized using multiple stress non-recoverable creep compliance, percent recovery and （SBS） modified asphalt with different use levels （by creep recovery（MSCR） test at 64 ℃ and 70 ℃. Then, their stress sensitivities derived from this test were ana- lyzed. According to AASHTO MP 19-10 specification, high temperature performance grading was conducted on modified asphalt with different use levels of SBS. The results show that with the increase of use level of SBS, the non-recoverable creep compliance of modified asphalt shows downward trend and percent recovery of modified asphalt shows upward trend, especially for SBS at lower content, which indicates that the increasing use level of SBS is more prominent for the improvement of high temperature performance of modified asphalt at lower SBS content. There is no clear relationship between the stress sensitivity of non-recoverable creep com- pliance or percent recovery of modified asphalt and the use level of SBS. The stress sensitivity of non-recovera- ble creep compliance or percent recovery of modified asphalt becomes basically prominent at elevated test tem- perature. It is more effective to discriminate the high temperature performance of modified asphalt with differ- ent use levels of SBS when 70 ℃ is set as basic grading temperature.