不同试验方法的老化沥青疲劳性能研究

通过旋转薄膜烘箱试验(RTFOT)和压力老化试验(PAV),对70~#基质沥青、苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)改性沥青、高黏沥青(HV)和基于化学改性原理的SBS/橡胶复合改性沥青(SRC)进行短期老化和长期老化,采用温度扫描试验、时间扫描试验、多重应力蠕变恢复(MSCR)试验和线性振幅扫描(LAS)试验对4种沥青的疲劳性能进行了研究.结果表明:SRC沥青的疲劳性能和抗老化能力最佳;温度扫描试验不能很好地区分不同沥青的疲劳性能差异;时间扫描试验可有效表征4种沥青的疲劳性能,但其耗时较长;MSCR试验中出现了平均弹性恢复率(R_(0.1)和R_(3.2))在长期老化之后大于短期老化之后的情况,其指标规律性和适用的沥青范围尚不明确;LAS试验可以表征沥青在重复荷载作用下的累积损伤发展过程,得到的损伤特征曲线和疲劳方程可有效评价各种沥青的疲劳性能.

Fatigue Property of Aged Asphalt Binders Using Different Experimental Methods

70# asphalt, styrene butadiene styrene copolymer(SBS) modified asphalt, high viscosity modified asphalt(HV) and a chemically modified asphalt, SBS/rubber compound modified asphalt(SRC) were subjected to short term and long term aging by using rolling thin film oven test(RTFOT) and pressure aging vessel(PAV) test. Their fatigue property were evaluated by temperature sweep test, time sweep test, multiple stress creep recovery(MSCR) test and linear amplitude sweep(LAS) test. The results indicate that the fatigue property of SRC and aging resistance are the best. Temperature sweep test does not well distinguish the differences in fatigue property of different asphalt binders. Time sweep test can effectively characterize the fatigue property of these four asphalts, but it costs too much time. MSCR test results show that the average elastic recovery rates(R0.1 and R3.2) of asphalt binders after long term aging are higher than that of short term aging, the regularity of this indicator and the range of applicable asphalt binders are not clear. LAS test can show the cumulative damage development process of asphalt binders under repeated loading, and the obtained damage characteristic curves and fatigue equations can effectively evaluate the fatigue property of different asphalt binders.