基于APT试验的红土粒料沥青路面开裂研究  

Research on Cracking of Laterite Granular Asphalt Pavement based on APT Test

作　　者：欧阳韦 周毅恒 陶泽峰 OUYANG Wei;ZHOU Yi-heng;TAO Ze-feng(Key Laboratory of Road and Transportation Engineering,Ministry of Education,Tongji University,Shanghai 201804,China;PowerChina Roadbridge Group Co.Ltd.,Beijing 100160,China)

机构地区：[1]同济大学道路与交通工程教育部重点实验室,上海市201804 [2]中电建路桥集团有限公司,北京市100160

出　　处：《公路》2022年第9期76-81,共6页Highway

基　　金：国家自然科学基金项目,项目编号51908427。

摘　　要：利用赤道几内亚红土粒料,修筑了以天然红土粒料为底基层,以水稳红土粒料和掺碎石红土粒料为基层的试验段,并用未筛分碎石基层做对比,采用足尺加速加载试验研究了红土粒料沥青路面的长期性能。通过统计加载过程的裂缝长度、数量和裂缝率的变化,监测沥青层动态应变,换算当量轴载次数等,对比了3种基层结构的使用性能。结果表明:3种结构均出现横向和纵向疲劳开裂,原因是轮迹带位置的车辙过大造成轮迹外侧产生较大的竖向剪应力、轮迹带沥青层底部出现较大的纵向应变,反复作用下出现纵向和横向裂缝;水稳红土粒料基层相比于掺碎石红土粒料和未筛分碎石基层,裂缝数量明显更多,总裂缝率更大,初裂时的当量标准轴次仅为另两种基层结构的1/3;掺碎石红土粒料的疲劳寿命超过900万次,说明掺碎石红土粒料表现出较好的抗疲劳开裂性能,而水稳红土粒料抗疲劳能力最弱;通过沥青层温度曲线与轮下纵向应变曲线背离的时刻可判断沥青层底的开裂时机。In this paper,the test section is built with natural red clay granule from Equatorial Guinea as the subbase course,water stabilized red clay granule and gravel mixed red clay granule as the base,and the test results are compared with the unscreened red gravel base.The long-term performance of laterite granular asphalt pavement is studied by full-scale accelerated loading test.The performance of three basic structures is compared by counting the variation of crack length,number and crack rate during loading process,monitoring the dynamic strain of asphalt layer,and conversion of equivalent axial load times.The results show that transverse and longitudinal fatigue cracks occur in all three structures.The reason is that large ruts at the wheel track location cause large vertical shear stress on the outside of the wheel track,large longitudinal strain on the bottom of the asphalt layer of the wheel track,and longitudinal and transverse cracks occur under repeated action.The number of cracks and the total crack rate of water-stabilized laterite granular base are significantly more than those of gravel mixed laterite granular base and unscreened gravel base,and the equivalent standard axial order of initial crack is only 1/3 of that of the other two base structures.The fatigue life of gravel mixed laterite is more than 9 million times,indicating that gravel mixed laterite also has better fatigue cracking resistance,and water stable laterite has the weakest fatigue resistance.The cracking at the bottom of asphalt layer can be judged by the time when the temperature curve of asphalt layer deviates from the longitudinal strain curve under the wheel.

关 键 词：沥青路面 红土粒料 足尺加速加载试验 疲劳开裂 裂缝率 

分 类 号：U416.217[交通运输工程—道路与铁道工程]