【作者】 张俊杰；

【导师】 邹桂莲； 李伟雄；

【作者基本信息】 华南理工大学 ， 交通运输工程（专业学位）， 2020， 硕士

【摘要】 随着再生沥青路面技术在全世界范围内广泛地应用,对沥青再生的研究涌现了丰硕的成果,也取得了重大的进展。然而由于目前尚不确定再生沥青混合料中新旧沥青具体的融合程度和实际的扩散状态,导致无法精确指导再生沥青混合料设计及预测其路面力学行为。因此,深入认识新旧沥青融合、扩散机理,表征及解析新旧沥青融合程度与扩散均质化情况,对于指导沥青混合料精确再生,提升沥青路面再生品质有重大意义。首先,通过比选及分析新旧沥青常用的示踪剂及观测手段,提出了基于荧光粒子表征和激光扫描共聚焦显微镜结合的试验方法和具体实施步骤。确定了新旧沥青融合、扩散三维观测及量化表征的可行性方案。针对替代新旧集料引入的木质模拟集料,通过对其表面打磨处理,消除其自发荧光以及保证沥青膜厚度统一的前提下对沥青用量修正等步骤,实现了样品制备的标准化。随后,针对激光扫描共聚焦显微镜仪器本身的噪点及深度方向亮度衰减、损失等问题,分别利用自阈值中值滤波算法、基于深度经验参数亮度衰减函数、基于景深及焦平面的亮度权重系数分配等对荧光强度图像进行图像降噪、光线散射及吸收矫正、图像分割与特征提取等共聚焦预处理步骤。确保对新旧沥青融合、扩散过程正确量化及表征。根据新旧沥青融合后的荧光强度衰减函数提出基于面积法的融合程度定义,并引入均质化系数来表征新旧沥青扩散的均质化情况。最后,基于上述开发的新旧沥青融合、扩散的观测及表征方法,分别解析了在施工接触阶段和路面服役状态下新旧沥青的融合程度及扩散均质化情况,分析了加热温度、加热时间,新旧集料上不同的融合及均质情况等影响因素,发现温度比时间的影响更为显著,因此施工接触阶段比路面服役转态对新旧沥青的融合有更大的影响,而由于新旧集料上的新旧沥青比例不同,新集料上混合后的沥青的均质化情况更佳。此外,根据图像处理技术和激光扫描共聚焦显微镜的验证分析,更小粒径的新集料会有更多的旧沥青转移,而这会进一步影响新旧沥青融合和扩散过程。更多还原

【Abstract】 With the extensive application of reclaimed asphalt pavement technology all over the world,many fruitful researches make significant progress on reclaimed asphalt.However,due to the uncertainty of the degree of blending and actual diffusion state of the virgin and reclaimed asphalt,it is hard to accurately guide the recycled asphalt mixture design method and predict the mechanical behavior of asphalt pavement.Therefore,to characterize and analyze the degree of blending and diffusion homogenization of the virgin and reclaimed asphalt could help deeply understand the blend and diffusion mechanism,and are also of great significance for guiding the accurate recycling of asphalt mixtures and improving the recycling quality of asphalt pavement.Firstly.Comparing the tracers and observation methods commonly used to analyze the blend of new and reclaimed asphalt,an experimental design method and specific implementation steps based on the fluorescent particle characterization and laser scanning confocal microscope were proposed.The feasibility plan of three-dimensional observation and quantitative characterization of the blend and diffusion of new and reclaimed asphalt was determined.As substitute to virgin and RAP aggregate,the pretreatment steps were conducted in aggregates simulated by wooden,including the process of polishing the surface,the elimination of its auto-fluorescence and the correction of the amount of asphalt to ensure the uniformity of the asphalt film thickness.the standardization of sample preparation was achieved.Secondly.In order to address the noise and depth attenuation and loss of the laser scanning confocal microscope,the self-threshold median filter algorithm,the brightness attenuation function based on depth experience parameters,and the distribution of brightness weight coefficients based on depth of field and focal plane were determined.Meanwhile,Confocal preprocessing steps for fluorescence intensity image such as noise reduction,light scattering and absorption correction,image segmentation and feature extraction were performed to ensure correct quantification and characterization of the blend and diffusion processes for the virgin and reclaimed asphalt.According to the decay function of fluorescence intensity after the blend of virgin and reclaimed asphalt,the definition about the degree of blending based on area method was proposed,and the homogenization coefficient was introduced to characterize the diffusion homogenization.Finally.Based on the observation and characterization methods above for the blend and diffusion of the virgin and reclaimed asphalt,the degree of blending and diffusion homogenization on the construction phase and the pavement service status were separately analyzed.Influencing factors such as the heating temperature,heating time,different blend and homogenization on virgin and RAP aggregate were compared.It was found that heating temperature has more significant effect than heating time.Therefore,the blend and diffusion on construction phase has a greater impact than on the pavement service status.There are different proportion of virgin and reclaimed asphalt between the virgin and RAP aggregates,and the diffusion homogenization on the virgin aggregate was better than on RAP aggregate.In addition,on the basis of the verification analysis of image processing technology and laser scanning confocal microscope,virgin aggregates hold smaller particle size will be transferred more reclaim asphalt,which will further affect the blend and diffusion process of virgin and reclaimed asphalt.更多还原