上面层改性沥青混合料低温性能综合对比评价

Comprehensive comparative evaluation of low-temperature performance for modified asphalt mixtures in upper surface layer

【目的】分析足尺路面试验环道所用7种上面层细粒式改性沥青混合料的低温性能。【方法】通过小梁低温弯曲、中梁线收缩系数和法国M2F梯形梁动态模量3种室内试验开展研究及相关性分析,并应用多指标试验结果的无量纲归一化赋权求和法进行综合对比评价。【结果】最大弯拉应变、应变能密度、线收缩系数、复模量和相位角均可作为改性沥青混合料低温性能的合理评价指标;对比改性沥青类型,采用低温延性强的SBS改性沥青制备的混合料低温性能最优,橡胶沥青混合料的次之,掺抗车辙剂能增强SBS改性AC类混合料的低温性能;对比矿料合成级配,SMA类的低温性能最优,SBS改性AC类中粗集料含量越低,其低温性能越好;多孔排水式高黏SBS改性PAC类具有优良的黏弹性和低温收缩性能。【结论】评价结果可为环道沥青路面低温性能长期监测对比提供参考。

[Purposes]The paper aims to analyze the low-temperature performance of seven kinds of fine grained modified asphalt mixture for upper surface layer used in the full-scale pavement test track.[Methods]Three kinds of laboratory experimental research and correlation analysis were carried out,including low-temperature bending test with small beam,linear shrinkage coefficient test with middle beam,and dynamic modulus test with French trapezoidal beam.Then the dimensionless normalized weighted summation method of multi-index test results was used for comprehensive comparative evaluation.[Findings]The maximum flexural strain,strain energy density,linear shrinkage coefficient,complex modulus and phase angle can be used as the reasonable evaluation indexes for the low-temperature performance of the modified asphalt mixture.For the effect of the type of modified asphalt,Compared with the types of modified asphalt,the mixture prepared by SBS modified asphalt with strong low temperature ductility has the best lowtemperature performance,followed by the rubber asphalt mixture,and the addition of anti-rutting agent can enhance the low temperature performance of SBS modified AC type mixture.For the effect of the gradations of mineral aggregate,SMA type has the best low-temperature performance,while the lower the coarse aggregate content of SBS modified AC type,the stronger the lowtemperature performance.Porous drainage high-viscosity SBS modified PAC type has excellent viscoelasticity and low-temperature shrinkage performance.[Conclusions]The evaluation results can provide reference for long-term monitoring and comparison of low-temperature performance in the test track asphalt pavement.