岩沥青复合改性沥青流变性能

Rheological properties of rock asphalt composite modified asphalt

为改善岩沥青改性沥青的流变性能,使其更好地应用于实际工程,分别添加不同掺量的胶粉、SBS和岩沥青,制备得到胶粉/岩沥青复合改性沥青(CR/RACMA)和SBS/岩沥青复合改性沥青(SBS/RACMA),采用针入度、软化点和黏度试验筛选改性剂掺配方案,应用频率和温度两种扫描模式下的动态剪切流变(DSR)和弯曲梁流变(BBR)试验分析岩沥青复合改性沥青的流变性能,利用Black曲线探讨岩沥青复合改性沥青的时温等效原理有效性及黏弹特性,并通过多应力蠕变恢复试验评价岩沥青复合改性沥青的抗永久变形能力.结果表明,CR/RACMA较SBS/RACMA具有更好的高温性能和温度敏感性;CR/RACMA较SBS/RACMA具有更优的PG分级,其中添加18%胶粉和5%岩沥青的CR/RACMA的PG分级最优;SBS/RACMA具有更加明显的时温依赖性,而CR/RACMA不适用于时温等效原理;CR/RACMA较SBS/RACMA具有更高的弹性成分和更小的不可恢复应变,其中添加18%胶粉和5%岩沥青和添加14%胶粉和12%岩沥青的复合改性沥青表现出相近的抗永久变形能力.综合流变性能试验分析得到18%胶粉和5%岩沥青是岩沥青复合改性沥青的合理掺配.

In order to improve the rheological properties of rock asphalt modified asphalt to be better employed in practical engineering,the crumb rubber/rock asphalt composite modified asphalt（CR/RACMA） and SBS/rock asphalt composite modified asphalt（SBS/RACMA） were produced with different contents of crumb rubber,SBS and rock asphalt,respectively.A comparative performance evaluation of rock asphalt composite modified asphalt was conducted by laboratory tests,in which the penetration,softening point and viscosity tests were employed to screen the composition scheme of modified additives,and then the rheological properties of rock asphalt composite modified asphalt were studied by using the dynamic shear rheometer（DSR） with temperature and frequency sweep,and bending beam rheometer（BBR） tests,the effectiveness of time-temperature superposition principle and viscoelasticity characteristics were discussed for the rock asphalt composite modified asphalt by the Black curve,also,the multiple stress creep recovery（MSCR） test was performed to evaluate the resistance to permanent deformation of rock asphalt composite modified asphalt.The results show that the CR/RACMA exhibits high temperature performance and temperature sensibility better than the SBS/RACMA.The CR/RACMA performs superior PG grade than the SBS/RACMA,and the CR/RACMA containing 18% crumb rubber and 5% rock asphalt performs the best PG grading among the all of tested asphalt binders.The SBS/RACMA indicates obvious time-temperature dependence by the Black curve analysis,however,the time-temperature superposition principle can not be employed in the CR/RACMA investigated.The CR/RACMA shows a higher elastic component and smaller non-recoverable strain than the SBS/RACMA.The CR/RACMA both containing 18% crumb rubber/5% rock asphalt,and 14%crumb rubber/12% rock asphalt exhibit the approximate resistance to permanent deformation.The 18% crumb rubber and 5% rock asphalt in the rock asphalt composite asphalt are proposed as proper composition by the rheological properties tests analysis.