Analytical derivation of permeability and numerical simulation of fluid flow in hot-mix asphalt
Analytical derivation of permeability and numerical simulation of fluid flow in hot-mix asphalt
复制标题
DOI：
10.1061/(asce)0899-1561(2004)16:5(487
复制
发表时间：
2004-09-01
影响因子：
3.2
通讯作者：
Cooley, A
中科院分区：
文献类型：
--
作者：
Masad, E;Birgisson, B;Cooley, A
渗透性是影响热拌沥青混合料（HMA）性能的重要性能。它是压实作用力和HMA的几个性质如沥青含量以及集料的形状和尺寸分布的函数。由于测量渗透率的实验室和现场方法不同，以及影响其值的因素之间的相互作用，很难开发出一个将渗透率与影响HMA渗透率的所有因素准确联系起来的分析方程。本文提出了一个简单的沥青混合料渗透性近似公式。它利用了骨料的空隙率和表面积。该方程是经验性的，但它是根据众所周知的Kozeny-Carman方程计算颗粒材料的渗透率。开发的方程被成功地用于拟合渗透率数据收集的几项研究进行现场和实验室测量的HMA渗透率。建立了热拌沥青混合料中空气空隙率梯度对水流流型影响的有限元模型。使用X射线计算机断层扫描仪测量沥青混合料子层之间的空隙率梯度百分比。这些子层的渗透率使用开发的方程计算，并用作有限元模型的输入。模拟结果表明，HMA中的空隙率梯度在水平方向上促进横向流动，在垂直方向上减少流动。
Permeability is an important property that influences the performance of hot-mix asphalt (HMA). It is a function of compaction effort, and several properties of HMA such as asphalt content, and the shape and size distribution of aggregates. Due to the different laboratory and field methods for measuring permeability, and the interaction among the factors that influence its value, it would be difficult to develop an analytical equation that accurately relates permeability to all factors contributing to HMA permeability. This paper presents a simple equation for approximating the permeability of asphalt mixes. It utilizes the percent air voids and surface area of aggregates. The equation is empirical but it is derived based on the well-known Kozeny-Carman equation for calculating the permeability of granular materials. The developed equation was used successfully to fit permeability data collected from several studies that carried field and laboratory measurements of HMA permeability. A finite element model was developed to investigate the influence of the gradient of percent air voids in HMA on water flow patterns. The x-ray computed tomography was used to measure the percent air void gradients among sublayers of the asphalt mix. The permeability of these sublayers was calculated using the developed equation, and used as an input to the finite element model. The simulation results show that air void gradients in HMA encourage lateral flow in the horizontal direction and reduce the flow in the vertical direction.