摘要
为了准确、快捷地测算沥青混合料空隙率,利用CT和数字图像处理技术识别了3种级配类型(AC,SMA和开级配沥青磨耗层OGFC)、2种成型方法(马歇尔击实和旋转压实)和多种压实功的沥青混合料试件的内部空隙特征,提出了沿着试件高度方向三段式(顶部、中部和底部)划分方法,分析了各部分的层数所占比例和计算空隙率对沥青混合料试件整体计算空隙率(沿试件高度方向所有划分截面分析计算得到的空隙率)的影响规律,定义了部分贡献值(部分层数所占比例与部分计算空隙率乘积),由此建立了沥青混合料空隙率预测方法,并与整体计算空隙率进行了比较,检验了该预测方法的计算精度。结果表明:与沥青混合料试件的实测空隙率相比,在标准压实功下,马歇尔击实和旋转压实AC混合料试件的整体计算空隙率分别增大7.5%和18%,SMA混合料试件的整体计算空隙率分别增大19%和22%,而OGFC混合料试件的整体计算空隙率均减小约20%;中部层数所占比例与中部计算空隙率,以及中部计算空隙率分布对沥青混合料试件整体计算空隙率具有重要控制作用,根据中部贡献值与整体计算空隙率关系建立的预测方法(其中采用中部15个截面确定中部计算空隙率)得到的预测整体计算空隙率与整体计算空隙率结果一致性较好。
To measure and calculate volume of air voids of asphalt mixtures rapidly and accurately, the characteristics of air voids of inner structure of asphalt mixtures specimens produced by three types of aggregate gradation （AC, SMA, and OGFC）, two compaction methods （Marshall compaction and gyratory compaction） and multi-compaction efforts were identified by using CT and digital image processing （DIP） techniques. A three-segment （top, middle and bottom） partition approach along the height of the specimens was put forward, theeffects of the percentage and the calculated volume of air voids of each segment on the overall calculated volume of air voids （the calculated volume of air voids from all single cross section along the height of specimens） of asphalt mixtures specimens were analyzed, and the contributing value of each segment （multiplying percentage and calculated volume of air voids of each segment） was defined, thus a prediction method of volume of air voids of asphalt mixtures was established. Moreover, the accuracy of the prediction method was examined through comparing the overall calculated volume of air voids. The results show that the overall calculated volumes of air voids of AC mixtures specimens increase by 7. 5% and 18%, and those of SMA mixtures increase by 19% and 22%, comparing to the testing results of volumes of air voids of the specimens, whereas those of OGFC mixtures decrease approximately 20% in terms of the Marshall and gyratory compaction with standard compaction efforts, respectively. The percentage and the calculated volume of air voids of the middle segment, and the distribution characteristics of it display a significant controlling influence on the overall calculated volume of air voids. The overall calculated volume of air voids is quite consistent with the volume of air voids from the prediction method based on the relationship between the contributing value and the overall calculated volume of air voids of the middle segment, in which the calculated volume of air voids of the middle segment is determined by the fifteen cross sections in the middle segment.
出处
《中国公路学报》
EI
CAS
CSCD
北大核心
2016年第8期12-21,42,共11页
China Journal of Highway and Transport
基金
国家自然科学基金项目(51308084)
中央高校基本科研业务费专项资金项目(3132014223)
关键词
道路工程
沥青混合料
CT
空隙率
预测
road engineering
asphalt mixture
CT
volume of air void
prediction
