基于DSR直接拉伸试验的沥青高温粘聚性分析

采用动态剪切流变仪(DSR)直接拉伸试验研究了60℃时改性沥青老化(RTFOT)前、后的粘聚性。绘制了σ-ε关系曲线,并对曲线进行双指数拟合;采用应力峰值σmax、峰值对应位移ε0、拉力功W以及指数方程拟合参数A1、A2作为沥青高温粘聚性的评价指标。研究结果表明:老化前TPS高粘沥青粘聚性各项指标最优;改性剂来源不同、掺量相同的SBS改性沥青粘聚性差异较大,其中以791改性沥青粘聚性最好,1301次之,4303最差。橡胶粉/791SBS复合改性沥青的σmax、ε0、W以及拟合参数A1、A2均远小于791改性沥青;RTFOT老化后,改性沥青粘聚性发生了较大变化,1301改性沥青各项指标最优、其次为4303,TPS高粘沥青和791改性沥青的粘聚性较差,橡胶沥青的粘聚性远小于其它类型改性沥青。

Modified Asphalt Cohesion Based on Tensile Test of DSR

Cohesion of different modified asphalts were investigated before and after rotated thin film oven tests(RTFOT)by direct tensile test of dynamic shear rheology(DSR).σ-ε curve was fitted by double exponential,choosing peak stress σmax,peak displacement ε0,pulling power W,fitting parameters A1,A2as evaluation indexes.The results indicate that tough polystyrene(TPS)high viscosity asphalt has the best cohesion performance,three kinds of styrene butadiene styrene(SBS)modified asphalt with the same content but different modifiers have great discrepancy on cohesion:σmax、ε0、W、A1and A2of crumb/791SBS modified asphalt were far less than those of 791SBS modified asphalt.The results also indicate that cohesion of different asphalts change obviously after RTFOT,cohesion of TPS,791 modified asphalt decrease dramatically,but the 1301 modified asphalt has a better performance than that before RTFOT and other kinds of asphalt.The crumb rubber asphalt has a poor cohesion performance compared with other asphalt,either before or after RTFOT.