基于界面3D构造的沥青铺装层层间粘合形成机制与致损机理

The interlayer state exerts a significant influence on the serviceability of the pavement structure. Most of existing mechanical models assume that the interface between adjacent layers is smooth, which is far from the actual situation. In addition, it is difficult to reveal the interface characteristics based on macroscopic phenomenology. Consequently, the primary focus of this research proposal is closely linked to the 3D spatial structure of the asphalt layer interfaces using 3D laser scanner and X-ray computed tomography (CT) technologies. In this regard, mechanical interlocking between two layers caused by aggregate embedment will be analyzed from microscopic aspect through the 3D digital image reconstruction. Based on the direct shear test between asphalt layers, characterization method for mechanical interlocking formed between the surfaces of asphalt layers is proposed, and interlocking features at interfaces are investigated. Considering the interfacial structure of asphalt pavement as well as the frictional and adhesive effects formed by bonding materials, the influence of several parameters, such as interface morphology, tack coat application rate, temperature and shear force on the interface strength is quantitatively analyzed. An interface adhesion mechanics model based on the morphological characteristics of the interface will be established to reveal the interface adhesion mechanism. Based on the single-factor and multi-factor interaction of tack coat type and dosage, temperature, moisture, and contamination, the experimental and theoretical analysis results are used to study the temporal characteristics of interface status and performance. Moreover, the interrelationship between parameters mentioned above will be sought, the damage model of interface deterioration will be established, and combining with the numerical simulation analysis of interlayer damage evolution, the mechanism of damage between layers will be comprehensively revealed. Findings of this study will provide theoretical basis for the design and optimization of the interface between asphalt layers.

层间状态对铺面结构服役性能具有重要影响，现有基于宏观现象学的层间模型假设层间界面为平面，与实际不符，难以从源头上揭示层间问题的内生本因。本项目紧扣沥青铺装层层间空间构造特征，拟采用3D激光表面扫描、CT空间扫描及数字图像重构技术，获取其界面形态，从细观角度剖析层间嵌锁效应，提出该效应表征方法；结合层间直剪试验，分析界面形态与层间摩阻行为关系，探明层间嵌锁特性。通过对洒铺粘层油后的层间界面形态获取及层间“压-直剪”、“切-拉拔”试验，明确界面形态、粘结剂量、环境温度、侧向力等因素对层间摩阻与粘联效应的交互作用关系，建立层间粘合力学模型，阐明层间粘合形成机制。以“油、热、水、污”等因素单独和共同时程作用为切入点，通过层间构造扫描及性能试验，研究界面状态与层间性能的时变特征，构建层间性能衰变模型，结合层间损伤演化数值模拟分析，综合揭示层间致损机理。研究成果将为沥青铺面层间设计与优化提供理论基础。

鉴于现有基于宏观现象学的层间模型假设层间界面为平面，与实际不符，难以从源头上揭示层间问题的内生本因。基此，本研究对沥青铺装层层间界面3D构造特征、层间粘合形成机制及其致损机理等问题进行了研究，主要研究成果包括：1）研发了沥青复合试件层间界面无损分离方法，应用高精度三维激光扫描和点云逆向重构技术，实现了“双界面”作用下的层间界面无损分离并复现了形貌三维数字；2）定义并计算了层间界面的三维“接触”与“嵌锁”效应，揭示了混合料空间结构和级配差异对两种效应的影响机理；3）计算了典型沥青层层间界面的细观峰态指标差异以及层间隔离膜的残损率差异，比较了层间界面的细观三维形态指标差异，厘清了界面细观峰态特征与层间隔离膜残损率间的关系，确立了表征界面三维细观形貌特征的关键指标，建立了宏细观作用效应下的层间抗剪强度预测模型，揭示了其层间强度形成机理；4）分析了粘结材料、温度、油量、侧向力等因素对层间界面摩阻-粘联效应的影响，确定了基于区域环境温度特征的增强型基-面层层间粘结材料适宜组合方式；5）研究了不同粘结组合下的层间强度和疲劳寿命的特性，构建了基于熵权-TOPSIS钢桥面防水粘结材料组合体系优选模型，揭示了沥青层层间粘合形成机制；6）研究了温度、加载频率、压应力及剪切应力幅值等外因素下的层间疲劳性能演变规律，建立了基于ISS & SSDR双指标的层间疲劳寿命预测模型；7）提出了模拟实际路况的层间应力状态的室内试验方法，构建了路面实际工况因素与室内斜剪试验参数之间的映射方程，量化评估了路面实际工况对层间抗剪强度和疲劳性能的影响；8）进行了不同层间污染条件（油、热、水、污）下的层间直剪、压剪耦合及拉拔试验，研究了不同污染条件下的热沥青粘层和乳化沥青粘层的层间强度和疲劳性能的衰变规律，提出了界面污染程度的合理控制范围。研究成果可为层间性能测试评价、层间强化处置设计提供技术基础支撑。