多面层结构体系下相变储热沥青路面的取向热诱导机理研究

High surface temperature of asphalt pavement is very easy to cause accelerated thermo-oxidative ageing of asphalt on pavement surface and high-temperature distresses such as rutting, aggravate urban heat island effect, and also lead to car blowout. Phase change heat storage asphalt pavement, which absorbs and stores latent heat during phase change process, has a notable cooling effect on pavement surface. However, current studies are inclined to discuss the cooling performance by using single-layer asphalt mixture. The reduced thermal conductivity of phase change heat storage asphalt mixture, together with the low heat transfer efficiency in the control asphalt middle and bottom layers, prevents external heat quickly entering asphalt pavement and forms heat accumulation on pavement surface, causing a reduced cooling effect on pavement surface. The project aims to accelerate the transfer efficiency of surface heat to internal pavement by applying phase change asphalt mixture in different asphalt layers and then performing oriented heat induction in other asphalt layers. The adaptability relationship between phase change temperature of heat storage layer and its temperature characteristic is analyzed by establishing a heat storage-transfer numerical model of asphalt pavement. And then the oriented heat-induced methods under different heat storage asphalt layers are explored. A design method of heat storage-transfer induced structure of asphalt pavement is finally proposed. The project can provide guidance for the practical application of phase change heat storage asphalt pavement.

夏季沥青路表高温极易造成路表沥青加速热氧老化和车辙等高温病害，加剧城市热岛效应，还可引发汽车爆胎等安全问题。相变储热沥青路面通过相态转化吸收并存储潜热，是一种具有显著路表降温效果的路面形式。然而，既有研究偏于采用单层沥青混合料试件研究其降温性能。由于相变储热沥青混合料的导热性能普遍低于普通沥青混合料，以及普通沥青中下面层的热量缓慢传递，路表热量难以快速进入路面内部而在路表形成热积累，导致路表降温效果折减。为此，本项目提出分别在不同沥青面层应用相变储热沥青混合料，并对储热层外的沥青面层进行取向热诱导的研究思路，以加速路表热量向路面内部传递。通过建立沥青路面储-传热数值分析模型，分析不同储热沥青层的相变温度与该层温度特性的适应性关系，探索不同沥青层储热条件下沥青路面内的取向热诱导方法，最终提出基于路表降温的多面层结构沥青路面储-传热诱导结构设计方法，为相变储热沥青路面的工程应用奠定基础。

夏季沥青路面高温极易造成路表沥青加速热氧老化和车辙等高温病害，加剧城市热岛效应，还可引发汽车爆胎等安全问题。相变储热沥青路面通过相态转化吸收并存储潜热，是一种具有显著路面降温效果的路面形式。基于传统路用相变材料易泄露而对沥青混合料性能造成负面影响的现实问题，本项目对直掺相变沥青的性能劣化机理进行深入分析后，分别提出了陶粒基和水泥基复合相变材料的制备方法并进行了性能表征。水泥基复合相变材料的实测相变焓达37.47J/g，并可大幅度提高沥青胶浆的高温和疲劳性能。在对相变储热沥青混合料和热改性沥青混合料进行热物参数测试的基础上，建立了沥青路面储-传热数值分析模型。分别将相变储热沥青混合料用于路面上面层和中面层，系统研究了路面内的热诱导对相变储热沥青路面热行为和温度特性的影响。结果表明，路表和内部温度分布特性与相变储热沥青混合料层位和热改性沥青混合料的布置均有关系，应根据路面降温需求精准设计路面相变储热与热诱导方式。本项目提出的水泥基复合相变材料可为路面降温、除冰等提供沥青混合料制备方法；提出的沥青路面储-传热结构及其传热特性分析可为路面调温方法提供理论借鉴，最终为相变储热沥青路面的工程应用奠定基础。