基于流变的复合增强剂改性沥青高低温性能影响

Influence of High and Low Temperature Performance of Composite Reinforcing Agent Modified Asphalt Based on the Rheological Properties

为改善沥青的高温性能,充分发挥各材料特性,按比例复掺两种改性剂(热塑性高聚物、木质纤维素),得到一种复合增强剂用于沥青的双掺改性,通过动态剪切流变试验(DSR)对复合增强剂改性沥青高温稳定性进行评价,基于时温等效原理构建复数模量主曲线观察沥青黏弹转化规律;并采用弯曲流变梁试验(BBR)评价复合增强剂的低温改性效果。试验结果表明,复合增强剂改性沥青的感温性优于SBS改性沥青(SBS含量为5%)和基质沥青;且可以显著改善沥青的高温性能,改善效果随着复合增强剂掺量的增加而提高,但随温度上升而减弱;掺加复合增强剂后,疲劳因子G*·sinδ相较于基质沥青降低,表现出较差的抗疲劳性;观察沥青蠕变劲度s和蠕变速率m的变化情况,发现复合增强剂低温改性效果欠佳。

In order to improve the high-temperature performance of asphalt,give full play to the characteristics of each material,and two modifiers(thermoplastic high polymer,lignocellulose)are mixed in proportion to obtain a composite reinforcing agent for double-doping modification of asphalt.The high temperature stability of composite reinforcing agent modified asphalt is evaluated through dynamic shearing Shear rheological test(DSR).Based on the time-temperature equivalence principle,the complex modulus main curve is constructed to observe the viscoelastic transformation of asphalt.The bending rheological beam test(BBR)is used to evaluate the low temperature modification effect of composite enhancer.The test results show that the composite reinforcing agent modified asphalt has better temperature sensitivity than SBS modified asphalt(SBS content is 5%)and matrix asphalt;and it can significantly improve the high temperature performance of asphalt,and the improvement effect increases with the addition of composite reinforcing agent,but weakens with increasing of the temperature;after adding composite reinforcing agent,the fatigue factor is lower than that of matrix asphalt,showing poor fatigue resistance;after observing changes in creep s and creep rate mof asphalt,it is found the composite reinforcing agent has poor curing effect at low temperature.