多孔沥青混合料细观孔隙特征和声学行为特性研究

With the expansion of urban scales, rapid development of urbanization and motorization, the urban road traffic noise problems are getting more serious. This proposal herein presents a research approach to study pore structure and acoustic characteristics of porous pavement materials based on materials and structure characteristics of porous pavement. Stationary wave method、CT testing and digital image processing techniques will be jointly employed in this research to study the microscopic void characteristics and acoustic property of the porous pavement materials. As a result of this research, the following objectives will be reached: 1) the underlying principles on which macro materials' composition characteristics of porous pavement materials influence the sound absorption performance and microscopic void characteristics will be revealed; 2) the constitutive relationship among the composition of the mixture, microscopic void characteristics and sound absorption performance will be established. Additionally, based on the studies of microscopic void characteristics, this research will analyze how the space distribution of the void and microscopic structure influence the noise reduction mechanism and efficiency on the tire noise. The findings of this research will finally optimize the design of both the materials composition and structure combination of porous pavement. Finally, the microstructure model of porous asphalt mixture was established by using physical geometrical and electro-acoustic principle to analyze the influence of the pore structure characteristics on the acoustic performance of porous asphalt mixture. The research objective is to study the influence that air void, structure thickness and sound absorption coefficient made on the noise reduction efficiency of the porous pavement. With porous pavement materials' properties as inputs, this study will propose a method for selecting porous pavement materials and structure according to different function requirements. Compared with the existing studies in this area, the proposed study herein will provide theoretical and technical support for the application of the porous pavement.

针对目前城市道路交通噪声问题日益严重，本项目以多孔路面材料与结构特征为基础，研究多孔路面孔隙结构与声学特性。采用吸声系数驻波管测定法，结合计算机层析扫描和数字图像处理技术，研究多孔路面材料细观孔隙特征和声学特性，揭示多孔路面材料宏观材料组成对其细观孔隙特征和声学性能的影响规律，建立混合料材料组成-细观孔隙特征-声学性能的本构关系；基于细观孔隙特征的研究成果，分析孔隙的空间分布、细观构造对轮胎噪声的降噪机理与效能，优化多孔路面材料组成设计；基于物理几何原理及电声学理论，构建材料孔隙结构特性参数与声学参数之间的关系模型，研究孔隙率、吸声系数、结构厚度等参数对多孔路面吸声降噪效能的影响，结合多孔路面材料特性，提出基于功能要求的多孔路面材料和结构选型方法，为多孔路面的应用提供理论和技术支撑。

项目针对城市道路交通噪声日益严重等问题，以降噪为研究重点深入研究了多孔路面空隙结构与声学特性。以计算机层析扫描和数字图像处理技术为主要研究手段，分析了多孔路面材料宏观材料组成对其细观孔隙特征和声学性能的影响规律，建立了混合料材料组成-细观孔隙特征-声学性能的本构关系；分析了孔隙的空间分布、细观构造对轮胎噪声的降噪机理与效能；构建了材料孔隙结构特性参数与声学参数之间的关系模型，研究了孔隙率、吸声系数、结构厚度等参数对多孔路面吸声降噪效能的影响；提出了基于功能要求的多孔路面材料和结构选型方法。研究结果表明：材料厚度越大，比流阻越大，吸声性能下降；多孔沥青混合料吸声系数峰值随着空隙率的增大而提高，并且吸声系数峰值均集中出现在频率范围在900～1000Hz附近，峰值在形成的同时随着空隙率的增大向高频方向移动；随着结构因子的增大，峰值吸声系数减小，两者呈线性变化趋势；随着主孔直径的增加，吸声系数峰值变小，而吸声系数峰值对应的频率值没有发生改变；空隙率和主孔直径一定的情况下，吸声系数随着连通孔直径Da减小呈现先增大后减小的变化趋势，在Dp/Da比值为5时出现吸声系数峰值；空隙率不变，不同主孔直径情况下，吸声系数随着Dp/Da比值的变化的趋势是相同的，最大吸声系数随着Dp/Da比值的增大，先增大后减小，最佳的Dp/Da比值在4～7之间；随着空隙率的增加，峰值吸声系数所对应的频率略有增加，并且峰值吸声系数随空隙率的增加呈下降趋势；随着厚度的增加，吸声系数曲线第一峰值增大，所对应的频率减小，吸收的频率范围由高频向低频转移。项目的研究成果可指导基于降噪性能的多孔路面材料设计，为多孔路面的应用提供理论和技术支撑。