基于数字图像技术的再生骨料沥青混合料骨架接触类型量化表征

新-旧骨料的接触类型及其比例决定了再生骨料沥青混合料的力学强度和耐久性.对比了再生骨料与天然骨料的物化特性差异,分析了AC-20C型再生骨料沥青混合料的路用性能,并通过截取试样断面图像、提取骨料接触点对再生骨料沥青混合料中不同骨架接触类型及其比例进行了量化表征.结果表明,与天然骨料相比,再生骨料针片状含量和表观密度降低...

Quantitative Characterization of Contact Type of Recycled Aggregate Asphalt Mixture Based on Digital Image Technology

The mechanical strength and durability of recycled concrete aggregate asphalt mixture(RCA-AM)depend on the contact type and its proportion of new and old aggregates.In this paper,the physical and chemical characteristics of recycled concrete aggregates(RCA)and natural aggregates(NA)were compared and the road performances of AC-20C RCA-AM were analyzed.The different skeleton contact types and their proportions in the RCA-AM were quantified by intercepting the section images of the specimen and extracting the aggregate contact points.The results show that the content of needlelike aggregates and apparent density of the RCA are decreased while the crushing value and water absorption are increased.The high temperature performance of the asphalt mixture is obviously improved and the low temperature performance,water stability and fatigue performance are decreased to a certain extent.Except the water stability,the low temperature and fatigue performance still meet the requirements of the specification.The classification and discrimination principles of skeleton contact types were proposed and the contacts between RCA were the main contact type in RCA-AM.The proportion of this kind of contacts reaches 85.7%at 30%replacement rate.This study attempts to evaluate the influence of RCA on the performances of RCA-AM from the perspective of skeleton contact characteristics,which lays a foundation for further establishing the relationship between macro performance and micro contact parameters.