随着秦岭山区经济活动日益频繁，塑料制品在该区域的广泛应用，大量废旧塑料已成为亟待解决的环保难题；塑料改性沥青低温性能和相容性差，严重影响其进一步推广使用。因此，本文针对秦岭山区废旧塑料的不同类型，将其添加到不同的基质沥青中，进行废旧塑料改性沥青及其混合料性能研究工作，主要内容如下：

（1）对秦岭山区主要废旧塑料情况进行调查分析与归类整理，并优选适用于沥青改性的废旧塑料类型。发现秦岭山区废旧塑料性能与地区分布及外界环境联系较小，采用热风循环加热熔融造粒工艺制备的废旧塑料颗粒性能稳定、造价低且环保。此外，依据不同废旧塑料改性沥青性能，优选氨解后的聚对苯二甲酸乙二醇酯（PET）为后续试验的废旧塑料改性剂。

（2）对废旧塑料改性沥青制备参数进行研究，并从基本性能、贮存稳定性和流变性能等方面对比分析SK沥青、京博沥青、壳牌沥青、PET改性SK沥青、PET改性京博沥青、PET改性壳牌沥青。通过响应曲面法拟定四因素四响应试验，提出本文废旧塑料改性沥青制备参数为基质沥青种类选择京博沥青，废旧塑料掺量为4.7%，剪切时间为55min，剪切温度约为187℃。此外，PET可显著改善沥青的高温及抗老化性，且PET改性京博沥青的性能优于PET改性SK沥青和壳牌沥青。

（3）借助扫描电镜与红外光谱等测试手段，结合分子动力学模拟，分析废旧塑料-沥青间作用机理。结果表明PET能够与沥青中的蜡和轻质组分紧密结合，从而显著改变沥青的结构并提升其性能。改性作用主要以物理方式实现，且PET在沥青中呈现均匀分散的状态，与沥青之间展现出了良好的相容性。

（4）验证了废旧塑料改性沥青AC-13混合料路用性能。结果表明废旧塑料改性沥青混合料满足现行规范要求，低温抗裂性略低于SBS改性沥青，但高温抗车辙性和水稳定性与SBS改性沥青相当，均达到90%以上。

With the increasingly frequent economic activities in the Qinling mountainous area, plastic products in the region's wide range of applications, a large number of waste plastics has become an urgent solution to the environmental problems. The poor low-temperature performance and compatibility of plastic-modified asphalt seriously affects its further popularization and use. Therefore, in this paper, for the different types of waste plastics in the Qinling mountainous area, it is added to different base asphalt to carry out the research work on the performance of waste plastic modified asphalt and its mixtures. The main contents are as follows:

(1) Investigate, analyze and categorize the main waste plastics in the Qinling mountainous area, and preferably select the types of waste plastics suitable for asphalt modification. It was found that the performance of waste plastics in the Qinling mountainous area is less related to the regional distribution and external environment. The performance of waste plastic granules prepared by hot air circulating heating and melting granulation process is stable, low cost and environmentally friendly. In addition, based on the performance of different waste plastics modified bitumen, polyethylene terephthalate (PET) after ammonolysis was preferred as the waste plastic modifier for the subsequent test.

(2) The preparation parameters of waste plastic modified asphalt is studied, and the difference between SK asphalt, Jingbo asphalt, Shell asphalt, PET modified SK asphalt, PET modified Jingbo asphalt, PET modified Shell asphalt are compared and analyzed from the aspects of basic performance, storage stability and rheological properties. The four-factor four-response test was formulated through the response surface method, and the parameters for the preparation of waste plastic modified asphalt in this paper were proposed to be the choice of the type of base asphalt, Jingbo asphalt, the doping amount of waste plastics was 4.7%, the shearing time was 55min, and the shearing temperature was about 187°C. In addition, PET can significantly improve the high temperature and aging resistance of asphalt, and the performance of PET-modified Jingbo asphalt is better than PET modified SK asphalt and Shell asphalt.

(3) With the help of scanning electron microscopy and fourier transform infrared spectroscopy, combined with molecular dynamics simulation, analyzed the interaction mechanism between waste plastics and asphalt. The results show that PET is able to bind closely to the waxes and light components in asphalt, thus significantly changing the structure and improving the performance of asphalt. The modification was mainly realized by physical means, and PET was uniformly dispersed in the asphalt, showing good compatibility with the asphalt.

(4) The road performance of waste plastic modified asphalt AC-13 mixtures was verified. The results show that the waste plastic modified asphalt mixture meets the current specification requirements, low-temperature cracking resistance is slightly lower than SBS modified asphalt, but high-temperature rutting resistance and water stability are comparable to SBS-modified asphalt, both reaching more than 90%.