基于细观结构的排水沥青路面空隙长周期堵塞规律与降噪功能衰减机理研究

The voids of permeable asphalt pavement are easily clogged in the application process, which often cause the performance deterioration i.e. drainage and noise reduction. It has become a main restricting bottleneck for popularization and application of the technology. The basic scientific research on long-term void clogging characteristic and its influence on the noise reduction deterioration mechanism will be carried based on the voids distribution at the time and space using mesostructure. There are three main themes in the project. Firstly, the influence of the complex factors including initial void ratio of asphalt mixture, the contaminant properties at the pavement surface, repeated load and void maintenance mode on the voids distribution and drainage will be analyzed by the developed long-term clogging experiment. Secondly, the void distribution information of permeable asphalt pavement at the time and space will be characterized by X-ray CT scanning, digital image processing and fractal theory. Relational model between void distribution characteristic parameter and void ratio and permeability coefficient will be developed in the void clogging process. Finally, the noise characteristic of permeable asphalt pavement will be determined in the clogging process by the method of standing wave tubes and accelerating-falling tire. Based on this, the influence of void distribution mesostructure on the noise reduction deterioration mechanism will be discussed. The project aims to reveal the void distribution characteristic at the time and space and noise reduction deterioration mechanism of permeable asphalt pavement in the void clogging process from the view of mesostructure. It can provide theoretical and technological evidence to prevent effectively the void clogging, maintain and restore the noise reduction function for permeable asphalt pavement.

排水沥青路面应用过程中空隙容易被堵塞，导致排水和降噪功能衰减，成为了制约该项技术推广的主要瓶颈。本项目以排水沥青路面空隙的细观结构在时间和空间上的分布特性为研究对象，对空隙的长周期堵塞规律及其降噪功能衰减机理进行基础科学研究。具体内容包括：通过建立的“长周期”堵塞实验分析混合料初始空隙率、路表污染物、重复荷载和空隙维护方式等耦合因素对空隙率和透水性的影响；综合X-ray CT扫描、数字图像处理和分形理论对排水沥青路面堵塞空隙的时间和空间特性进行精细描述，构建空隙分布特征参数与空隙率和透水系数的关系模型；采用驻波管法和轮胎下落法研究空隙堵塞过程中排水沥青路面的噪声特性，分析堵塞空隙的细观结构对其降噪功能衰减的影响机理。本项目旨在从细观结构角度揭示排水沥青路面空隙长周期堵塞过程中的时空分布规律与降噪功能衰减机理，为有效防治排水沥青路面空隙堵塞以及保持和恢复降噪功能提供理论和技术依据。

排水沥青路面具有安全性高、舒适性好和低噪音的特点，是提升道路表面使用功能特性的最佳路面形式。但是，排水沥青路面在通车一段时间后其内部空隙会被泥土、胎屑、落叶等污染物堵塞，致使其排水以及降噪功能严重衰减，其已成为制约排水沥青路面发展的一个关键问题。本研究以排水沥青路面空隙的细观结构在时间和空间上的分布特性为研究对象，采用X-ray CT 扫描技术研究排水沥青路面初始空隙率、路表污染物属性与空隙维护方式等因素作用下堵塞颗粒在排水沥青路面空隙内的迁移规律和沉积特性以及由此导致的空隙分布规律，并结合噪声试验揭示排水沥青路面堵塞空隙的细观结构对其降噪功能衰减的影响机制。取得了一些原创性成果：1）建立了针对排水沥青路面空隙的长周期堵塞-清洗试验方法，揭示了混合料参数、堵塞物、养护措施等因素对排水沥青路面长周期堵塞的影响机制，构建了路面真实服役状态下的堵塞因子和渗水系数统一预测模型；2）基于计算流体力学-离散元耦合（CFD-DEM）精确地模拟了堵塞颗粒在空隙中的迁移过程，发现了堵塞颗粒的运动深度规律，揭示了排水沥青路面的长周期堵塞机理，验证并预测了排水沥青路面的空隙寿命；3）采用驻波管法和轮胎加速下落法阐明了排水沥青路面降噪功能的影响因素和堵塞过程中降噪功能的衰减规律，建立了排水沥青路面吸声系数和A计权声压级的相关性，构建了排水沥青路面在初始状态和堵塞状态下降噪能力的预测模型；4）基于X-ray CT扫描技术量化表征了排水沥青路面内部细观空隙在堵塞过程的演变规律，探明了细观空隙变化对渗水和降噪性能的影响机制，建立了细观空隙参数与渗水和降噪能力的相关模型，实现了基于细观结构的不同使用寿命下排水沥青路面渗水和降噪功能的预测。本项目的成功实施为客观评价排水沥青路面空隙堵塞提供了理论与技术依据，对有效防治排水沥青路面空隙堵塞及保持和恢复排水、降噪功能具有重要的理论意义和参考价值。