基于CT图像的水泥稳定RAP材料细观结构研究  

Meso-structure of Cement Stabilized RAP Materials Based on CT Images

作　　者：阳虎 单丽岩[1] 李志伟 YANG Hu;SHAN Liyan;LI Zhiwei(School of Transportation Science and Engineering,Harbin Institute of Technology,Harbin 150090,China)

机构地区：[1]哈尔滨工业大学交通科学与工程学院,哈尔滨150090

出　　处：《材料导报》2024年第1期66-71,共6页Materials Reports

基　　金：国家自然科学基金(51978218)。

摘　　要：研究沥青混合料回收料(RAP)掺加对混合料组成与结构特性的影响,可为其应用在路面结构层以及材料参数设计提供理论支撑。基于X-ray CT与图像处理技术,提出了一种可区分新旧集料的冷再生混合料细观结构识别方法,分析了RAP团粒、旧集料与新集料的细观特征的差异,研究了RAP的掺加对水泥稳定材料细观结构的影响。结果表明:提出的细观结构识别方法可准确识别水泥稳定RAP材料断面图像中的空隙、砂浆、新集料与旧集料四类区域,完整地保留新旧集料的原始轮廓、大小与形状等信息;RAP团粒中分布较多初始微细裂缝,且旧集料扁平比与棱角性系数均大于新集料;RAP的掺加一方面增加了再生混合料中体积小于0.01 mm3的微空隙与大于100 mm3的大空隙数量,导致材料的密实度降低;另一方面也增加了材料的沥青砂浆含量,提高了再生混合料的平均砂浆膜厚度,使混合料骨架内部力传导更均匀;提高水泥稳定RAP材料中石屑与碎石比例,可使材料的平均空隙体积减小、平均砂浆膜厚度增大,从而改善再生混合料的骨架填充状态。Studying the influence of reclaimed asphalt pavement(RAP)on the composition and structural characteristics of mixtures can provide theoretical support for their application in pavement structure layer and material parameter design.This paper proposed a method for identifying the meso-structure of cold recycled mixtures,both new and old aggregates,based on the X-ray CT and image processing technology.The diffe-rences in the meso-structure characteristics of RAP,old aggregates,and new aggregates were analyzed,and the effects of RAP on the meso-structure characteristics of the cement-stabilized RAP materials were studied.The results demonstrate that the proposed meso-structure recognition method can accurately identify the void,mortar,new aggregate,and old aggregate in the section image of cement-stabilized RAP material and completely retain the original outline,size,and shape information of new and old aggregates.Compared with the new aggregate,the old aggregate has a higher flat ratio and angular coefficient.Further,several micro air voids and cracks are present in RAP-granular.The addition of RAP increases the number of micro air voids(volume less than 0.01 mm 3)and large voids(volume greater than 100 mm 3)in the recycled mixture,resulting in the reduction of material compactness;further,the asphalt mortar content of the material increases,the average mortar film thickness of the recycled mixture improves,and the internal force conduction of the mixture skeleton becomes more uniform.Increasing the proportion of RAP materials stabilized with cement can reduce the average void volume and increase the average mortar film thickness,thereby improving the skeleton filling status of the recycled mixture.

关 键 词：RAP 水泥稳定材料 X-ray CT 细观结构 冷再生技术 

分 类 号：U414[交通运输工程—道路与铁道工程]