随着我国经济社会的发展以及公路建设重心的转变，公路总里程与养护里程持续增长，导致每年产生大量废旧混合料，且目前废旧混合料的回收再利用主要局限于单一路面结构层，不足以处理每年增产的废旧混合料。陕北地区作为我国重要的能源和化工产业基地，受地理及交通环境所限，其在道路建设和维护方面所面临的挑战更为严峻。因此，本文基于陕北地区沥青路面调查分析，结合再生沥青路面调研情况，同时将废旧混合料应用于基层和面层，初步拟定冷热再生（冷再生基层-热再生面层）沥青路面结构，综合室内试验、数值模拟等技术手段，研究了废旧混合料冷热再生后的性能恢复，分析了结构层不同再生层厚度对冷热再生沥青路面结构的力学影响，并推荐冷热再生沥青路面典型结构，以推动冷热再生沥青路面结构在实际工程中的应用。主要研究内容如下：

（1）调查分析陕北地区的自然环境条件、交通量和沥青路面结构，总结不同公路等级常用沥青路面结构类型，结合再生沥青路面结构调研分析，初步拟定陕北地区重交通等级下不同公路等级的冷热再生沥青路面结构。

（2）对不同沥青混合料回收料（RAP）掺量下的热再生沥青混合料进行高温稳定性、低温抗裂性、水稳定性及动态模量测试，研究其性能特性与RAP掺量的规律。结果表明，使用热再生沥青混合料作为面层，在路用性能及力学性能方面可以满足路用要求。随着RAP掺量的增加，热再生沥青混合料的高温稳定性和动态模量得到提升，而其低温抗裂性和水稳定性出现降低。当RAP掺量达到40%时，混合料性能最佳，同时，在满足所有性能指标的前提下，RAP的最大掺量可达45%。

（3）以乳化沥青作为再生结合料，采用高温稳定性、水稳定性、抗压强度、抗压回弹模量及动态模量试验，评价不同RAP与水泥稳定碎石回收料（RAI）掺配比对冷再生混合料性能的影响。结果表明，使用乳化沥青冷再生混合料作为基层，在路用性能及力学性能方面可以满足路用要求。随着RAP掺量增加和RAI掺量减少，冷再生混合料的动稳定度、冻融劈裂强度、抗压强度、抗压回弹模量和动态模量逐渐降低，抗拉强度和柔化程度提高。综合乳化沥青冷再生混合料的各项性能和实际工程情况，RAP:RAI:新集料=30:50:20（方案1）的总体性能最佳，建议RAP掺量不超过40%为宜。

（4）根据初拟的陕北地区冷热再生沥青路面结构，构建路面结构有限元模型，研究冷再生层厚度和热再生层厚度对路面结构的力学响应与验算指标的影响规律，推荐了适用于陕北地区重交通等级下不同公路等级的冷热再生沥青路面典型结构，并将其与无再生层沥青路面结构进行对比。推荐陕北地区重交通等级的高等级公路热再生中面层厚度为7cm，冷再生上基层厚度为12cm；二级公路的热再生下面层厚度为7cm，冷再生上基层厚度为13cm。

With the development of China's economy and society, as well as the shift in the focus of highway construction, the total mileage and maintenance mileage of highways continue to grow. This leads to the generation of a large amount of waste mixtures every year. Currently, the recycling and reuse of waste mixtures are mainly limited to a single pavement structural layer, which is insufficient to handle the annually increasing waste mixtures. As an important energy and chemical industry base in China, Northern Shaanxi, limited by geography and traffic environment, faces more severe challenges in road construction and maintenance. Therefore, based on the survey and analysis of asphalt pavements in the Northern Shaanxi, combined with the investigation of recycled asphalt pavement, this study preliminarily proposes a cold and hot recycled (cold recycled base layer-hot recycled surface layer) asphalt pavement structure, which applies waste mixtures to both the base layer and the surface layer. Comprehensive indoor tests, numerical simulation and other technical means were used to investigate the performance recovery of waste mixtures after hot and cold recycled. The mechanical influence of different recycled layer thicknesses of the structural layer on the cold and hot recycled asphalt pavement structure was analyzed. Furthermore, the typical structure of cold and hot recycled asphalt pavement was recommended to promote the application of cold and hot recycled asphalt pavement structure in practical engineering. The main research contents are as follows:

(1) The natural environmental conditions, traffic volume and asphalt pavement structure types in Northern Shaanxi were investigated and analyzed to summarize the commonly used asphalt pavement structure types for different grades of highways. Combining the investigation and analysis of recycled asphalt pavement structure, the preliminary formulation of the cold and hot recycled asphalt pavement structure of different highway grades under the heavy traffic level in Northern Shaanxi.

(2) High temperature stability, low temperature crack resistance, moisture stability and dynamic modulus were tested on hot recycled asphalt mixtures with different reclaimed asphalt pavement (RAP) content. The potential laws of its performance characteristics and RAP content were investigated. The results show that using hot recycled asphalt mixtures as surface layers can meet the road requirements in terms of road performance and mechanical properties. With the increase of RAP content, the high temperature stability and dynamic modulus of the hot recycled asphalt mixtures are improved, while its low temperature cracking resistance and moisture stability are reduced. When the RAP content reaches 40%, the mixture has the best performance, and the maximum RAP content can be up to 45% under the premise of meeting all the performance indexes.

(3) Using emulsified asphalt as the recycled binding material, high temperature stability, moisture stability, compressive strength, compressive resilient modulus and dynamic modulus tests were conducted to evaluate the effects of different mixing ratios of RAP and reclaimed cement stabilized aggregate (RAI) on the performance of cold recycled mixtures. The results show that the use of emulsified asphalt cold recycled mixture as subgrade can meet the road requirements in terms of road performance and mechanical properties. With the increase of RAP content and the decrease of RAI content, the dynamic stability, freeze-thaw splitting strength, compressive strength, compressive resilient modulus and dynamic modulus of the cold recycled mixture gradually decreased, and the tensile strength and degree of flexibility increased. Comprehensive emulsified asphalt cold recycled mixture performance and the actual engineering situation, RAP: RAI: new aggregate = 30:50:20 (Scheme 1) of the best overall performance. It is recommended that the content of RAP should not exceed 40%.

(4) According to the preliminary proposed cold and hot recycled asphalt pavement structure in Northern Shaanxi, the finite element model of the pavement structure was constructed. The influence of cold recycled layer thickness and hot recycled layer thickness on the mechanical response and the check index of the pavement structure was investigated. Typical structures of cold and hot recycled asphalt pavements suitable for different road grades under heavy traffic conditions in Northern Shaanxi are recommended. Moreover, it is compared with the structure of asphalt pavement without recycled layer. It is recommended that the thickness of hot recycled middle surface layer of high grade highway with heavy traffic grade in northern Shaanxi is 7cm, and the thickness of cold recycled upper base layer is 12cm. The thickness of hot recycled lower surface layer of second grade highway is 7cm, and the thickness of cold recycled upper base layer is 13cm.