岩沥青/植物油复合再生沥青的流变性能

Rheological Properties of Rock Bitumen/Plant Oil Composite Regenerated Bitumen

针对现有植物油再生沥青的高温和弹性恢复性能不足的问题,利用岩沥青(Rock bitumen, RB)和植物油(Plant oil, PO)对老化沥青进行复合再生。通过三大指标和布氏黏度试验(Rotation Viscosity, RV)对再生沥青胶浆的物理性能进行分析,并通过频率扫描(Frequency sweep, FrS)、温度扫描(Temperature sweep, TeS)、多重应力蠕变恢复(Multiple Stress Creep Recovery test, MSCR)、低温弯曲梁流变(Bending Beam Rheological test, BBR)和线性振幅扫描(Linear Amplitude Sweep, LAS)等试验分别对再生沥青胶浆的高低温流变性能和疲劳性能的变化规律进行对比评价。结果表明,10%PO掺量可将沥青的常规物理性能基本恢复到老化前水平,但高温性能仍不足,RB/PO的复配可显著增强植物油再生沥青的高温弹性变形和恢复性能,并提高临界温度值(T);同时增大其屈服应变,延长疲劳寿命;此外,RB/PO的复配虽在一定程度上降低再生沥青的低温蠕变性能,但影响程度较低。综合考虑沥青胶浆的高低温和疲劳性能,10%PO和6%RB对老化沥青的复合再生效果最佳。

In view of insufficient high-temperature performance and elastic recoverability of the existing plant oil regenerated bitumen, in this study, rock bitumen(RB) and plant oil(PO) were utilized to regenerate the aged bitumen. The variation law on the physical properties of regenerated bitumen binder was analyzed through conventional three indexes test and Brookfield viscosity(RV) test, and the comparative evaluation on high-and low-temperature rheological characteristics and fatigue behavior of regenerated bitumen binder was implemented via frequency sweep(FrS), temperature sweep(TeS), multiple stress creep recovery(MSCR), bending beam rheological test(BBR) and linear amplitude sweep(LAS) test. The results demonstrated that: 10% PO content could restore the corresponding physical properties to the level before aging, except for insufficient high temperature properties. The combination of RB and PO could significantly improve the high temperature elastic deformation and recoverability of plant oil regenerated bitumen, and increase the critical temperature Tvalue;meanwhile, it could increase the yield strain and prolong fatigue life;furthermore, the combination of RB and PO might weaken the low-temperature creep properties to a certain extent with regarding to regenerated bitumen but the effect was relatively low. After comprehensive consideration of high and low temperature performance and fatigue properties, the utilization of 10%PO and 6%RB could achieve the optimum composite regeneration effect on the aged bitumen.