布敦岩沥青无机粉粒微观特征及改性机理

为了研究布敦岩沥青（Buton rock asphalt，BRA）中天然无机粉粒在沥青混合料改性过程中的作用，对布敦岩沥青中天然无机粉粒的特性和改性效果进行了分析. 利用X射线衍射（X-ray diffraction，XRD）、扫描电子显微镜（scanning electron microscopy，SEM）测定了无机粉粒的X射线衍射谱和微观图像；通过K值法和灰度图像处理，分析了布敦岩沥青中的天然无机粉粒的矿物组分、微观特征及其形成机制；采用动态剪切流变试验和混合料性能试验，测定了天然粉粒对胶浆和混合料性能的影响. 结果表明:布敦岩沥青中天然无机粉粒含有约85%的碳酸岩，主要由古海洋生物残骸形成；其余约15%成分为石英、云母和石膏，比例约为7∶6∶1，颗粒表面覆盖的层状和片状晶体构成的微观粗糙构造的面积可达80%以上；原始微观形貌特征和有机胶结料对粉粒微观构造的填充状态是影响天然粉粒改性效果的主要因素，以天然无机粉粒取代机制矿粉使沥青胶浆车辙因子最多提高0.524 kPa，动稳定度提高18.8%，冻融劈裂强度提高5.1%，冻融劈裂强度比提高至83.5%以上；复合改性时，天然无机粉粒能够作为助剂改善沥青质改性胶结料和沥青混合料的性能. 当采用天然沥青质改性时，无机粉粒使沥青胶浆车辙因子提高0.674～0.910 kPa，动稳定度提高21.1%～25.6%，冻融劈裂强度提高3.5%～5.6%，冻融劈裂强度比由85%提高至90%以上. 

Microstructural Characteristics and Modification Mechanism of Inorganic Fine Particles in Buton Rock Asphalt

The properties of natural inorganic fine particles in Buton rock asphalt (BRA) and the effects of asphalt modification on these particles were analyzed in order to study the role of the natural inorganic fine particles in the process of asphalt mixture modification. First, X-ray diffraction (XRD) patterns and microscopic images of the inorganic fine particles were obtained using X-ray diffraction and scanning electron microscopy (SEM). Secondly, the mineral composition, microscopic characteristics, and mechanism of the formation of the natural inorganic fine particles in BRA were analyzed through the K value method and grayscale image processing. Finally, the effects of the inorganic particles on the performances of mastic and asphalt mixtures were determined using the dynamic shear rheological test (DSR) and mixture performance tests. The results show that the natural inorganic fine particles in BRA contain approximately 85% carbonatite, which is mainly formed from the remains of ancient halobios and partially retained the primary structure. The content of non–carbonate inorganic minerals reaches 15%, of which the proportions of quartz, muscovite, and gypsum are approximately 7:6:1. The surface area of the particles covered by micro-rough structures composed of layered and tabular crystals can reach more than 80%. The preservation of the original microstructural characteristics, recovery, and the enhancement of the organic binder filling state of the microstructure are the main factors responsible for the modification effect of the natural particles. The partial substitution of artificial mineral particles by natural inorganic fine particles can increase the rutting factor of the asphalt mastic, dynamic stability, and freeze-thaw tensile strength by 0.524 kPa, 18.8%, and 5.1% respectively, and the tensile strength ratio can increase to more than 83.5%. The use of natural inorganic fine particles as an aid in compound modifiers improves the performance of the mastic and asphalt mixtures. When the mastic or mixture is modified with natural asphaltene, the natural inorganic fine particles increase the rutting factor of the asphalt mastic, dynamic stability, and freeze-thaw tensile strength by 0.674–0.910 kPa, 21.1%–25.6%, and 3.5%–5.6% respectively, and the tensile strength ratio increases from 85% to more than 90%.