道路沥青表面能参数测试结果的差异性研究

The adhesion between the asphalt binder and aggregates in a paving asphalt mixture can be quantified using the surface energy components of the asphalt binder and the aggregates. However, significant discrepancies have been identified in the measured surface energy components of the asphalt binder when choosing different sets of probe liquids, different test methods, or different periods of time to collect the test data during the same test. .In this project, the traditional Good-von Oss-Chaudhury (GvOC) theory of surface energy will be investigated in depth. The component classification and model construction of the GvOC theory will be evaluated to determine the limitations of formulating the polar component in the form of the geometric mean of the Lewis acid component and the Lewis base component. An experimental plan will be designed and executed to verify the assumptions in the GvOC theory so as to determine the feasibility of composing the polar component using the Lewis acid component and the Lewis base component. The Young-Dupre equations will be established and diagnosed to determine whether the systems of linear equations are ill-conditioned and/or have multicollinearity. As a result, any possible correlated surface energy components will be identified. The Wilhelmy Plate Method and the Sessile Drop Method will be evaluated to identify the causes that result in the differences in the measured contact angles. In the Wilhelmy Plate tests, special attention will be paid to the viscous forces applied to the glass plate and the probe liquid film attached to the asphalt surface. A model will be proposed to correct the measured dynamic contact angles via addressing the viscous forces and the attached liquid film. In the Sessile Drop tests, the time effect will be studied during forming and imaging the probe liquid droplets, and the images of the droplets will be processed using different methods for comparison. Methods will then be proposed to correct the errors in the measurements of the static contact angles and to process the droplet images more precisely. Consequently, a mathematical model will be developed to establish the relationship between the dynamic contact angles and the probe liquid properties, moving speed of the asphalt-coated glass plate and the static contact angles. Finally, an improved theoretic and experimental system will be proposed to determine the surface energy components of asphalt binders with satisfactory consistency.

沥青混合料中沥青与集料的黏附性能可通过分别测定两者表面能参数进行定量评价。但根据现有表面能理论与试验体系测得的沥青表面能参数常因化学试剂、试验方法、试验数据提取节段等不同产生显著的差异性。.本项目将深入分析现有表面能理论中表面能的分量组成、模型形式，从物理化学角度研究极性分量以酸碱分量几何平均值表示的局限性；检验现有理论的基本假设，从逻辑角度判断将极性分量分为酸、碱分量的可行性；诊断Young-Dupre方程组的病态程度及多重共线性，从数学角度分析各表面能参数的相关性。在试验方面，将量化插板法试验中试剂对沥青涂膜玻片的黏滞力及附着度，提出修正动态接触角的模型；研究静滴法试验中液滴形态的时效性及图像处理，提出控制静态接触角误差的方法；建立动态接触角与试剂性质、玻片运动速度、静态接触角等的关系模型。最终提出改进的表面能理论和更为完善的表面能试验体系，极大提高沥青表面能参数测试结果的稳定性。

沥青表面能可以用于定量评价沥青混合料中沥青—集料界面的黏附性能，但是基于现有表面能理论和试验体系确定的沥青表面能参数会因为试验方法、计算理论、化学试剂选取等产生明显差异。.本项目围绕现有表面能理论体系和测试方法中的误差来源，开展了以下研究工作：.（1）分析了现有表面能计算理论（单分量法、双分量法、三分量法）和测试方法（静滴法和插板法），从物理意义和数学计算角度，明确采用三分量法进行沥青表面能计算；基于接触角理论的静滴法和插板法均可以用于沥青表面能测试，但是二者在试验过程中均存在误差，导致两种方法下确定的沥青表面能无法统一。.（2）为解决沥青表面能测试过程中存在的误差，首先对静滴法展开研究，确定了静滴法测试沥青表面能过程中图像拍摄阶段与接触角测量阶段的误差来源，提出了优化方法，发展了一种优化改进的沥青静滴法试验方法；接着对插板法展开研究，明确了黏滞力与浸润速度对接触角测量的影响程度，提出优化方法，发展了一种优化改进的沥青插板法试验方法；最后建立了动态接触角和静态接触角的关系模型，统一了静滴法和插板法测试中的不一致性。.（3）为明确化学试剂种类造成沥青表面能参数测量差异性的原因，以插板法为例，分析了化学试剂的种类以及方程计算方法对沥青表面能测试过程中的影响，发展了一种优化改进的试剂组合与方程计算方法。.（4）分析了沥青特征官能团对沥青—集料黏附性、沥青黏韧性及沥青黏度的性能的影响，明确了沥青各特征官能团对其性质的影响规律。.本项目针对沥青表面能测试过程中的理论和试验方法展开研究，提出了更适用于沥青材料的表面能理论和试验体系，极大降低了沥青表面能参数测试结果的差异性，使得测量结果更加准确、可靠，有利于基于表面能理论的沥青与集料黏附性能定量评价方法的应用与推广，具有突出的理论与实践意义。