基于原子力显微技术的热再生混合料中新旧沥青融合程度量化指标和方法
Indicators and Method to Quantify the Degree of Blending Between Aged and Virgin Asphalt Binder in Hot Recycled Mixtures Based on Atomic Force Microscopy
李明宸 1刘黎萍 1邢成炜 2黄威棋1
作者信息
- 1. 同济大学道路与交通工程教育部重点实验室,上海 201804
- 2. 长安大学特殊地区公路工程教育部重点实验室,陕西西安 710064
- 折叠
摘要
厂拌热再生混合料中新旧沥青的融合程度对再生混合料设计及性能均有重要影响,目前已有较多学者开展了融合程度的量化研究,但现有量化方法在应用时大多需采用化学试剂对再生沥青进行抽提回收,这无疑会破坏混合料中新旧沥青真实的融合状态.基于原子力显微技术直接针对热再生混合料试件提出一种量化新旧沥青真实融合程度的方法.为此,首先在沥青层面探究了利用原子力显微技术中得到的力学、化学指标量化沥青融合程度的可行性,发现在单一沥青层面,DMT模量指标与宽带点光谱量化得到的羰基指数与沥青老化及融合特征相关性较好;接着选取DMT模量和羰基指数指标建立了完全混溶再生沥青纳观性能的预估方程;然后,在混合料层面利用不同来源的沥青对量化指标的适用性进行了检验,发现相较于羰基指数,采用DMT模量指标量化再生混合料中新旧沥青融合程度的误差更小;最后,基于该指标在混合料层面初步给出了直接量化厂拌热再生混合料中新旧沥青融合程度的方法;并以3种旧料掺量的再生混合料为例,对量化方法的应用进行了介绍.
Abstract
The degree of blending between virgin and aged asphalt in hot-plant-mixed recycled mixtures affects the design and performance of recycled mixtures.Numerous studies have been conducted to quantify the degree of blending between virgin and aged asphalt;however,most of the existing quantification methods require the use of chemical solvents to extract and recover recycled asphalt,which is detrimental to blending conditions.Therefore,the present study proposed a method to quantify the real degree of blending between virgin and aged asphalts based on atomic force microscopy(AFM),which is suitable for hot recycled mixture specimens.First,an investigation was conducted at the asphalt level to determine the feasibility of using nanomechanical properties obtained via AFM peak force quantitative nanomechanical mode(AFM PF-QNM)and chemical indicators obtained via AFM nano-infrared spectroscopy(AFM-IR)to quantify the degree of blending of asphalt.The results indicate that the DMT modulus and carbonyl indices obtained from the quantification of broadband point spectra of asphalt correlate well with asphalt aging and blending conditions.Thus,the DMT modulus and carbonyl indices were selected to establish prediction equations for the nanoscale properties of completely blended recycled asphalt.Subsequently,the applicability of the constructed equation was verified using different asphalt sources at the asphalt mixture level.At the asphalt mixture level,the nanoscale DMT modulus exhibits a higher accuracy than the nanoscale carbonyl indices in quantifying the degree of blending between virgin and aged asphalt in a mixture.Hence,a preliminary method for directly quantifying the blending conditions between virgin and aged asphalts in hot-plant-mixed recycled mixtures was introduced.The application of the prediction equation was presented using typical recycled mixtures with three reclaimed asphalt pavement(RAP)contents.
关键词
路面工程/新旧沥青融合程度/峰值力定量纳米力学模式/纳米红外光谱技术/热再生沥青混合料/DMT模量/羰基指数/预估方程Key words
pavement engineering/degree of blending/atomic force microscopy peak force quanti-tative nanomechanical mode/atomic force microscopy nano-infrared/hot recycled asphalt mix-tures/DMT modulus/carbonyl indices/prediction equation引用本文复制引用
基金项目
国家自然科学基金(51978521)
国家自然科学基金(51778483)
出版年
2024
NETL
NSTL
万方数据