热再生沥青混合料RAP分散情况的多尺度分析  

Multi-scale Analysis on RAP Dispersion in Recycled Hot Mix Asphalt Mixture

作　　者：陈铁军 CHEN Tie-jun(China Railway 16th Bureau Group Road and Bridge Engineering Co.,Ltd.,Beijing 101500,China)

机构地区：[1]中铁十六局集团路桥工程有限公司,北京101500

出　　处：《公路交通科技》2022年第12期17-26,共10页Journal of Highway and Transportation Research and Development

基　　金：中铁十六局集团科技项目(07ML3B-KYJS-2020-0001)。

摘　　要：沥青混合料回收料(RAP)在热再生沥青混合料(RHMA)中的分散情况会影响沥青路面的路用性能及耐久性。为探明热拌过程中RAP在RHMA中的分散情况,采用磁铁矿作为探针集料代替部分再生沥青混合料中新集料,结合抽提与旋转蒸发法获取了不同热拌时间下的融合沥青。在此基础上,采用流变试验、傅里叶红外光谱试验、凝胶渗透色谱试验、原子力显微镜试验分析了不同热拌时间情况下融合沥青的性能、组成以及微观形貌。通过荧光示踪法以及图像分析法探究了不同热拌时间下RAP在RHMA中的分散情况。结果表明:RHMA中融合沥青的复数剪切模量、弯曲蠕变劲度随拌和时间的增加而增加,蠕变速率则反之;融合沥青中羰基、亚砜基以及大分子含量与拌和时间呈正比;融合沥青“蜂状”结构的密度随拌和时间的增加而减小,平均“蜂状”结构面积则反之,因此,随着拌和时间的增加,RAP中老化沥青与新沥青之间的融合程度显著提高;随着拌和时间的增加,RAP中团聚颗粒在拌和过程中逐渐被破坏,进一步增加了RAP与新沥青、新集料之间的接触面积,促进了RAP表面老化沥青与新沥青之间的融合,加剧了融合沥青的老化程度。工程中,为保障RHMA的生产质量以及使用耐久性,建议在考虑经济与环境效益的基础上适当延长RHMA的拌和时间。The dispersion of RAP in recycled hot mix asphalt mixture(RHMA)affects the pavement performance and durability of asphalt pavement.To investigate the dispersion of RAP in RHMA during hot mixing duration,magnetite is used as probe aggregate to replace some new aggregate in recycled asphalt mixture,the blended asphalts in different hot mixing durations are obtained by extraction and rotary evaporation.On this basis,the performance,composition and micro morphology of blended asphalt under different hot mixing durations are analyzed by using rheological test,Fourier transform infrared spectroscopy test,gel permeation chromatography test and atomic force microscope test.the dispersions of RAP in RHMA in different hot mixing durations are investigated by fluorescence tracing method and image analysis method.The result shows that(1)the complex shear modulus and flexural creep stiffness of the blending asphalt in RHMA increase with the increase of mixing time,while the creep rate is on the contrary;(2)the contents of carbonyl group,sulfoxide group and macromolecule in blending asphalt are proportional to mixing time;(3)the density of the“bee-like”structure of the blending asphalt decreases with the increase of mixing time,while the average area of the“bee-like”structure is on the contrary,therefore,the blending degree between aged asphalt in RAP and virgin asphalt increase significantly with the increase of mixing time;(4)with the increase of mixing time,the agglomerated particles in RAP are gradually destroyed in the mixing process,further increasing the contact area among RAP,virgin asphalt and virgin aggregate,promoting the blending of aging asphalt and new asphalt on the RAP surface,and intensifying the aging degree of fusion asphalt,and promotes the blending between the aged asphalt and virgin asphalt on the surface of RAP and intensifies the aging degree of blending asphalt.In the project,to ensure the production quality and the durability of RHMA,it is recommended to extend the mixing time of RHMA appropri

关 键 词：道路工程 分散情况 荧光示踪法 沥青混合料回收料 拌和时间 

分 类 号：U416.26[交通运输工程—道路与铁道工程]