Study On The Preparation Of Mineral Powder-cellulose Composite Fiber And Its Reinforcement On The Asphalt And The Mix

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.