沥青-集料黏附作用评价方法综述

A Review on Evaluation Methods of Asphalt-Aggregate Adhesion

沥青与集料间的黏附作用是形成沥青混合料结构的重要影响因素,且直接关系到沥青混合料的结构强度、水稳性等主要性能,也对沥青混凝土路面的使用寿命有较大影响。因此,对沥青与集料间黏附作用方面的研究十分必要。典型的黏附作用评价方法可分为如下三类:(1)在石质基材(或其他材料)表面涂抹沥青层,对沥青层与基材界面施加垂直拉力或剪切应力,以沥青从基材表面剥离所需力的大小(或剪切强度)间接表征两者之间的黏附作用;(2)表面涂覆沥青的集料放入水中,水的作用使得沥青从集料表面剥落,以沥青从集料表面剥落的程度评价沥青与集料之间的黏附作用;(3)基于表面能理论,测试沥青与集料的表面能参数,从能量角度评价沥青-集料的黏附作用。我国《公路工程沥青及沥青混合料试验规程》(JTG E20-2011)中规定使用水煮法和水浸法来评价沥青-集料黏附性能,试验方法简单快捷,但测试结果受人为判断影响,缺乏定量评价指标。随着科学技术的进步,研究者逐渐将各种新技术运用到沥青-集料黏附性能检测中,如超声波模拟动水压力对传统水煮法进行改进,并应用高质量的图形处理系统使得沥青剥落程度指标得到更精准的量化;基于原子力显微镜技术(Atomic force microscope,AFM),在不同测试模式下进行微纳观尺度沥青-集料黏附作用评价,国外研究人员还依托神经网络模型,实现黏附性能的量化。随着原子力显微镜技术(AFM)的不断成熟,将该技术应用于对沥青-集料黏附作用的评价中已成为近年来的研究热点。同时,在研究人员的努力下,使用AFM新发展起来的测试模式测量沥青、集料的表面能及黏附功已取得突破性进展。随着对黏附作用研究的不断深入,一些研究新思路也开始出现,研究人员为了探讨在不同荷载作用下沥青与集料黏附性能的变化,针对“三明治”柱体试件采用动态力学分析仪(Dynamic mechanics analyzer,DMA)进行拉伸试验,分析沥青与集料拉伸黏结疲劳与加载应力之间的关系,将黏附与疲劳有机地联系在一起,同时以沥青胶浆(集料+矿粉)为研究对象,对其进行黏附疲劳测试,以沥青胶浆黏附疲劳失效表征沥青与细集料之间的黏附作用。本文通过回顾国内外沥青与集料黏附作用的研究发展历程,对沥青-集料黏附作用研究中的评价方法及研究现状进行综述,重点介绍四种沥青-集料黏附作用评价体系,并对各评价体系中评价方法的优缺点进行比较和评述,指出现有沥青-集料黏附性评价体系的不足,提出该领域未来的发展趋势和研究热点。以期为后续沥青-集料黏附性能试验方法改进研究和应用提供参考。

Typical adhesion evaluation methods can be classified into the following three categories:(i)smearing the asphalt layer on the surface of stone substrate (or other materials), applying vertical tensile or shear stress to the interface between the asphalt layer and the substrate, and indirectly characterizes the adhesion between asphalt and aggregates by the magnitude of force (or shear strength) when asphalt is peeled off from the substrate surface;(ii) the asphalt-coated aggregate is placed in water, and the action of water causes the asphalt to peel off from the aggregate surface. The adhesion between asphalt and aggregate is evaluated by the degree of asphalt peeling from the aggregate surface;(iii) based on the surface energy theory, the surface energy parameters of asphalt and aggregate are tested, and the asphalt-aggregate adhesion is evaluated by the energy parameters. Standard Test Methods of Bitumen and Bituminous Mixtures for Highway Engineering (JTG E 20-2011 ) in China specifies the use of boiling and water immersion methods to evaluate asphalt-aggregate adhesion properties. Although the test method is simple and fast, the results are influenced by human judgment and lack of quantitative evaluation indicators. With the development of science and technology, researchers have gradually applied various new technolofgies to the asphalt-aggregate adhesion performance test, such as ultrasonic simulation of hydrodynamic pressure to improve the traditional boiling method, the application of high-quality graphics processing system to quantify the degree of asphalt peeling. And based on atomic force microscope (AFM), the micro-nano scale asphalt-aggregate adhesion evaluation is carried out with different test modes. Neural network model is used to quantify the adhesion properties. With the continuous maturity of AFM, the application of this technology to evaluate asphalt-aggregate adhesion has become a research hotspot in recent years. At the same time, under the efforts of researchers, the newly developed test using AFM has made breakthroughs in measu- ring the surface energy and adhesion of asphalt and aggregates. Also some new research ideas have begun to appear. In order to investigate the changes in the adhesion properties of asphalt and aggregate under different loads, the researchers used dynamic mechanics analyzer (DMA) for tensile tests of “sandwich” cylinder specimens to analyze the relationship between asphalt and aggregate tensile bond fatigue and loading stress. Therefore, adhesion is associated with fatigue organically, and the asphalt mastic (aggregate + mineral powder) is taken as the research object, and the adhesion fatigue test is carried out. The adhesion between asphalt and fine aggregate is characterized by the adhesion fatigue failure of asphalt mastic. This paper reviewed the development history of asphalt and aggregate adhesion at home and abroad, comprehensively described the evaluation methods and studied the status of asphalt-aggregate adhesion. Four asphalt-aggregate adhesion evaluation systems were classified. The advantages and disadvantages of the evaluation methods in the evaluation system were compared. The shortcomings of asphalt adhesion evaluation system were presented, and the future development trends and research hotspots in this field were proposed. It provided the reference for the further improvement and application of asphalt-aggregate adhesion performance test method.