【作者】 陈晓龙；

【导师】 韩跃新；

【作者基本信息】 东北大学 ， 矿物加工工程， 2014， 博士

【摘要】 道路交通是人类文明发展进步的显性标志,而道路结构的现代化进程与路用材料的使用是息息相关的,自十九世纪上半叶沥青材料被应用于道路建设以来,沥青结构路面已经发展成为当今世界上最为普遍的路面结构形式,全球85%以上的高等级路面结构均为沥青混凝土路面。尽管如此,沥青也因其材料自身固有缺陷而导致了多种类型路面病害的发生,这就为大量沥青增强改性材料的研制与应用提供了广阔的发展空间,矿物粉体复合木质纤维便是其中一例。矿物粉体复合木质纤维是一种以木质素纤维为基体、非金属矿物粉体为表层涂覆材料的新型复合材料。本文从不同种类矿物粉体改性沥青的性能研究入手,详细考察了硅藻土、高岭土、钙基膨润土、钠基膨润土对重交通道路沥青路用性能的影响规律,评价其作为沥青改性材料的优劣,研究最终选定硅藻土作为复合纤维表层涂覆材料。本文研制成功了硅藻土复合木质纤维的制备方法,并在自主设计、搭建的复合纤维半工业生产线上完成其制备试验研究,以复合纤维灰分含量作为控制指标,详细考察了矿粉与纤维复合时间、浆体浓度和矿粉掺量各工艺条件对硅藻土复合纤维产品特性的影响规律,并确定了适宜的制备工艺条件。对该工艺制备的最终产品采用国家道路行业标准及方法进行了相关测试,所得结果均满足其筑路添加的应用要求。本研究继而开展了硅藻土复合木质纤维改性沥青及混合料的路用性能室内试验研究,采用针入度指数、当量软化点、当量脆点指标评价了复合纤维改性沥青的高温特性、低温特性及感温性能,结果表明改性沥青的上述性能均得到一定程度的改善,本研究还对比分析了复合纤维与其他不同类型的沥青改性材料对改性沥青性能的影响效果。在随后进行的马歇尔试验和车辙动稳定度试验中,硅藻土复合木质纤维增强SMA结构沥青混合料的性能也得到了证明,本文还通过纤维掺量试验确定了复合纤维在改性沥青及其混合料中的适宜掺加量。本文按照“由里及表、由微观进入宏观”的研究思路,从沥青的化学组成和胶体结构特性出发,运用红外光谱仪、扫描电镜、差示扫描量热仪、动态剪切流变仪及足尺路面加速加载试验机等技术手段,通过纤维-沥青界面作用过程分析、复合纤维在沥青中微观形态分析、改性沥青热分析、改性沥青流变学分析以及改性沥青混合料稳定性分析方法,重点深入探究复合纤维增强沥青及混合料的机理成因。研究结果表明复合纤维通过吸持轻质油分和吸附重质组分而改善沥青的胶体结构、缓释沥青中轻质组分而保持其富油特性、与沥青形成结合牢固的两相界面、在空间形成三维网络结构而增强了沥青的宏观力学性能,改善其热学特性,通过对沥青性能的改善继而传导至沥青混合料,进而增强沥青混合料的抗高温变形能力,使混合料表现出较高的稳定性和抗车辙能力。本文研制了一种新型沥青增强改性材料并完成了其半工业化制备,评价了产品的应用性能,分析了其增强机理,上述研究内容为矿物复合纤维的制备及在道路交通中的应用奠定了理论与实践基础。更多还原

【Abstract】 Road traffic is one of the dominant signs that mark the development and progress of human civilization, while the modernization process of the road structure is closely related to the use of road materials. Since the first half of the 19th century, when asphalt materials was used in road construction, asphalt pavement structure has grew into the most common form of the pavement structure in the world, and more than 85% of the world’s high-grade pavement structure are asphalt concrete pavement. However, asphalt material also caused various types of pavement diseases because of its inherent defects, which provides a broad space for development of bitumen modified material. The mineral powder and cellulose composite fiber is one example.The mineral powder and cellulose composite fiber is an advanced composite material, which is composited by non-metallic mineral powder and cellulose composite. In this paper, starting from the performance of different kinds of mineral powder modified asphalt, the effects of diatomite, kaolin, calcium bentonite and sodium bentonite on heavy traffic road pavement performance were detailed investigated. According to the result of the experiment, diatomite was selected to be used as the coating material of cellulose fiber.Based on the preparation process of cellulose composite fiber, preparation of diatomite-cellulose composite fiber was designed, and its preparation research was accomplished in the self-built semi-industrial production line. The effects of composite time, slurry concentration and mineral powder dosage on the characteristics of diatomite-cellulose composite fiber, and the optimal conditions for its preparation were determined. The properties of the product prepared by this process were tested using the national road standards and methods. The results indicated that the properties of diatomite-cellulose composite fiber achieved the requirements of application in roads added.The road performances of modified asphalt and its mixture were carried out. The high temperature performance, low temperature performance and temperature susceptibility of modified asphalt were evaluated respectively by equivalent softening point, equivalent breaking point and penetration index. The results showed that these performances of the modified asphalt were all improved obviously. The influences of different fibers on the technical properties of modified asphalt were also investigated. The results of Marshall and rut dynamic stability tests proved that diatomite-cellulose composite fiber could strengthen the performance of SMA asphalt mixture.The optimum dosage of diatomite-cellulose composite fiber in modifying asphalt and its mixture was determined according to dosage test.The strengthen mechanism was deeply discussed from the points of causes of the asphalt mixture rut, congeries state change of asphalt, sheer rheological and dynamic mechanical properties, interfacial structure between asphalt and fiber, interfacial interaction intensity and so, by means of APT, DMA, SEM, FT-IR, DSC and so on. The internal mechanisms of diatomite-cellulose composite fiber enhancing asphalt and its mixture performances were elaborated macroscopic and micro point of view. The results indicated that the diatomite-cellulose composite fiber strengthening the macroscopic mechanical properties of asphalt from the following three aspects: ① Diatomite-cellulose composite fiber would selectively adsorb saturates and aromatics in asphalt, by which asphalt colloid structure was converted. ②Combinative interface structure between asphalt and diatomite-cellulose composite fiber was formed.③ In the asphalt, diatomite-cellulose composite fiber distributed randomly in the three-dimensional space, and structure-asphalt nets was formed. Through the improvement of the properties of asphalt, the resistance to deformation of the asphalt mixture was enhanced, so that the mixture showed high stability and resistance to rutting.In the paper, a new type of asphalt and its mixture strengthening material named diatomite-cellulose composite fiber was produced. Its application performance and mechanisms of action in pavement was researched.The research by this paper can laid a theoretical foundation for the preparation of mineral composite fiber and its application in road traffic.更多还原