复合改性浇筑式沥青混合料疲劳性能分析

Analysis on Fatigue Performance of Composite Modified Guss Asphalt Mixture

为研究浇筑式沥青混凝土结构疲劳特性,优化桥面铺装结构整体性能,文章通过四点弯曲疲劳试验分析了复合改性沥青类型、油石比、应变水平及拌合温度等主要因素对劲度模量、加载次数、滞后角及耗散能指标的影响。结果显示:复合改性沥青类型及用量对疲劳性能存在显著影响,随沥青用量增加,GA沥青混合料的劲度模量呈下降趋势,破坏时的疲劳加载次数呈增加趋势;随应变水平的增加,劲度模量呈幂函数下降趋势,累积耗散能呈线性函数关系下降,破坏时的加载次数显著降低,劣化了疲劳寿命。汇总研究成果,合理地调整最佳沥青用量等参数,能够降低或避免GA沥青混合料老化问题,提高桥面铺装结构整体刚度及延长其使用寿命。

In order to study the fatigue characteristics of guss asphalt concrete structures and optimize the overall performance of bridge deck pavement structure,this article analyzed the impact of composite modified asphalt type,bitumen-aggregate ratio,strain level,mixing temperature,and other main factors on stiffness modulus,loading times,lag angles,and dissipative energy index through the four-point bending fatigue test.The results showed that the type and amount of composite modified asphalt have a significant effect on the fatigue performance,when the amount of asphalt increases,the stiffness modulus of GA asphalt mixture shows a downward trend,and the fatigue loading times during failure show an increasing trend;with the increase of strain level,the stiffness modulus decreases with the power function,the cumulative dissipated energy decreases with a linear function,the loading times during failure decreases significantly,and the fatigue life deteriorates;After summarizing the research results,the rational adjustment of the parameters such as optimum bitumen amount can reduce the or avoid the aging problem of GA asphalt mixture,improve the overall stiffness of bridge deck pavement structure and extend its service life.