研究沥青老化的最常见的评价参数有动态模量、回弹模量和延展性的损失,但其获取的方法复杂,本研究将采用试验方法简单而且应用广泛的间接拉伸试验,并确定实验室老化与现场老化的等效性.将在实验室中压实成型的圆柱形试件分别置于实验室和现场进行老化,再沿径向加载以确定间接拉伸强度和流值.第一组将试件在实验室的85℃烘箱中进行5、10、15、20和25 h的老化;第二组在现场进行1到12个月进行老化;第三组将松散混合料在135℃烘箱中进行8、16、32、48、72和100 h老化后成型并进行间接拉伸强度试验.本研究发现,实验室老化一天的IST值与现场老化一年的实验结果相当.松散混合料老化的结果表明,间接拉伸强度值随着老化时间延长,先增加后减小,存在峰值.总体而言,随着老化强度的增加,流值的减少,即表明材料脆性随着老化而增加.%While dynamic modulus,diametrical resilient modulus,and loss of ductility are the most common parameters to study aging,this study determines laboratory equivalence of field aging using an indirect tensile strength test for its simplicity and wide usages in asphalt concrete performance evaluation.Cylindrical samples were compacted in the laboratory,aged in the laboratory and field,and then loaded diametrically to determine indirect tensile strength value and flow number.The indirect tensile strength tests were conducted on six sets of compacted samples after subjecting them to 1,5,10,15,20,and 25 days of oven aging at 85 ℃ in the laboratory and on 11 sets of compacted samples after subjecting them to 1,2,3 and up to12-months of field aging.The ITS tests were also performed on a third set of samples whose loose mixes were subjected to 8,16,32,48,72 and 100 h oven aging at 135 ℃.As expected,indirect tensile strength of the laboratory (both compacted and loose) and field aged samples increase and flow number decrease with the aging period.It is found in this study that one-day laboratory aging is close to approximately one-year of field aging measured in terms of ITS value.Results from loose mix aging show that the ITS value increases with the conditioning period,reaches a peak and then decreases with the conditioning period.Overall,the flow number decreases as aging intensity increases,that is,the brittleness increases with aging.
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