AP-8改性沥青混合料疲劳性能分析

Fatigue Performance Analysis of AP-8 Modified Asphalt Mixture

为研究AP-8改性剂复合改性硬质沥青混合料的抗疲劳性能,优化桥面铺装材料的整体性能,文章以PMB-25沥青为参考对象,采用四点弯曲疲劳试验研究了不同配合比例的基础沥青(30^#沥青和70^#沥青)对劲度模量、疲劳加载次数、滞后角等指标的影响。结果显示:AP-8改性剂能够良好改善基质沥青的抗疲劳性能,随着油石比的增加,劲度模量值呈下降趋势,破坏时的疲劳加载次数和滞后角呈增加趋势;随着加载次数的增加,滞后角呈逐渐增加趋势,PMB-25沥青的滞后角随加载次数变化敏感性高于AP-8改性沥青;而随着应变水平的增加,AP-8改性沥青混合料的疲劳加载次数呈下降趋势,其中AH70^#改性沥青受应变水平影响高于AH30^#改性沥青;随拌合温度的增加,AP-8沥青混合料的劲度模量呈增加趋势,滞后角呈下降趋势,在180℃~240℃时,温度变化对滞后角影响更为显著,在240℃~260℃时,滞后角变化较为平缓。汇总研究成果可知,合理地调整最佳沥青用量或控制拌合温度,能够降低或避免AP-8沥青混合料老化问题,提高桥面铺装结构的整体刚度。

In order to study the fatigue resistance of AP-8 modifier composite modified hard asphalt mixture and optimize the overall performance of bridge deck pavement materials,with PMB-25 asphalt as reference object,this article uses four-point bending fatigue test to study the influence of basic asphalt (30^# asphalt and 70^# asphalt) with different mixing proportions on the stiffness modulus,fatigue loading times,and lag angle.The results show that AP-8 modifier can improve the fatigue resistance of matrix asphalt,and,with the increase of oil-stone ratio,the stiffness modulus decreases,and the number of fatigue loading and the lag angle at the time of failure show the increasing trend;with the increasing number of loading times,the lag angle increases gradually.The lag angle of PMB-25 asphalt is more sensitive than AP-8 modified asphalt with the increasing number of loading times;with the increase of strain level,the fatigue loading times of AP-8 modified asphalt mixture show a downward trend,wherein the AH70^# modified asphalt is more affected by the strain level than the AH30^# modified asphalt;with the increase of mixing temperature,the stiffness modulus of the AP-8 asphalt mixture increases,and the lag angle shows the downward trend,and,at 180℃~240℃,the temperature change has a more significant effect on the lag angle.At 240℃~260℃,the lag angle changes more gently.By summarizing the research results,reasonably adjusting the optimal asphalt dosage or controlling the mixing temperature can reduce or avoid the aging problem of AP-8 asphalt mixture and improve the overall rigidity of bridge deck pavement structure.