考虑黏层油迁移影响的OGFC面层空隙结构表征  

Characterization of OGFC pore structure considering the influence of tack coat migration

作　　者：宋卫民[1] 徐飞 吴昊[1] 詹易群 SONG Weimin;XU Fei;WU Hao;ZHAN Yiqun(School of Civil Engineering,Central South University,Changsha 410075,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075

出　　处：《中南大学学报（自然科学版）》2023年第7期2779-2787,共9页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(52008405,51778638);湖南省自然科学基金资助项目(2020JJ5744)。

摘　　要：为了保证沥青路面层间的充分黏结,在层间撒布黏层油是目前路面施工的必要工序。由于开级配磨耗层(OGFC)的大空隙结构,在压实过程中黏层油倾向于通过界面处OGFC的空隙向上迁移,从而影响界面处OGFC的空隙结构并进而影响其功能。本文选取2种下卧层材料、1种OGFC材料和4种黏层油掺量制作OGFC和下卧层组合试件;通过CT扫描、三维重构和一系列图像处理方法对OGFC面层的空隙结构进行表征和分析;选取截面空隙率、平均空隙半径和平均配位数对OGFC面层的空隙结构进行定量表征。研究结果表明:当层间不撒布黏层油时,OGFC面层的空隙率分布与密级配沥青混凝土的类似,呈现两端空隙率高、中间空隙率低的规律;当黏层油掺量为0.5、1.0和1.5 kg/m^(2)时,黏层油向上迁移,使得界面处OGFC的空隙率显著降低,并且黏层油掺量越大,迁移的高度越大;黏层油迁移对平均空隙半径和平均配位数的影响规律与空隙率的基本一致;下卧层的表面构造也会对黏层油的迁移造成显著影响。To ensure the adequate bonding between asphalt pavement layers,spraying tack coat is a necessary step in pavement construction.Because of the remarkable pore structure of open-graded friction course(OGFC),tack coat materials may migrate upward into OGFC,which affects the pore structure adjacent to the interface and further affects the functionality of OGFC.In this study,two types of underlying materials,one type of OGFC and four different tack coat dosages were selected to prepare the composite specimens.The pore structure of the OGFC surface layer was characterized and analyzed by CT scanning,3D reconstruction and a series of image processing methods.The cross-sectional porosity,average void radius and average coordination number were selected to quantitatively characterize the void structure of the OGFC surface layer.The results show that when no tack coat is applied,the porosities at two ends are large and porosity in the middle is low,and the cross-sectional porosity distribution of OGFC surface is similar to that of dense-graded asphalt concrete.When the tack coat dosages are 0.5,1.0 and 1.5 kg/m^(2),tack coat material migrates upwards,which significantly reduces the porosity of the OGFC adjacent to the interface,and the greater the amount of the tack coat is,the greater the migration height is.The influence of tack coat migration on the average pore radius and average coordination number is basically the same as that of the porosity.The surface structure of the underlying layer also has a significant impact on the migration of the tack coat.

关 键 词：开级配磨耗层 黏层油迁移 空隙率 平均空隙半径 平均配位数 

分 类 号：U414[交通运输工程—道路与铁道工程]