Investigation On The Performance Of Coal Gangue Powder/Brucite Fiber Composite Modified Asphalt Mixture

Coal gangue is one of the largest emissions of industrial solid waste in China. Up to now, there is few research result of coal gangue powder as a filler to modify the performance of asphalt mixture. Meanwhile, brucite fiber is the preferred natural substitute for asbestos, and it has the advantages of good performance and low price. The effect of brucite fiber on improving the performance of asphalt mixture needs to be further explored. In view of this, it is of great significance to carry out the investigation on the performance of coal gangue powder/brucite fiber composite modified asphalt mixture systematically and illuminate the applicability and effects in order to improve the resource utilization of coal gangue and brucite fiber in road engineering as well as enhance the service performance of asphalt pavement.In this paper, the potential conditions of using coal gangue powder as a modifier in asphalt mixture were explored on the basis of the analysis of the physical and chemical characteristics of coal gangue raw ore. Three different types of coal gangue powders were prepared(H1, H2, H3). Giving consideration to the high and low temperature performance, rheological method was adopted to define the reasonable powder-asphalt ratio of three coal gangue powder modified asphalt mortars. Using penetration test, Brookfield viscosity test, dynamic shear rheological experiment(DSR), dynamic thermodynamic analysis(DMTA) and other methods to investigate the mechanical properties, viscosity-temperature properties, rheological properties and phase behavior change of coal gangue powder/brucite fiber composite modified asphalt mortar. Analyzing the degree of improvement of gangue powder and brucite fiber modified asphalt binder under different types of conditions and contents. Through the rutting test, low-temperature bending test and freeze-thaw splitting test, the high-temperature stability, low-temperature crack resistance and water stability of coal gangue powder/brucite fiber modified asphalt mixture was researched. The influence significance of indexes of fillers and brucite fiber content on the road performance of asphalt mixture was analyzed with the grey entropy method. Based on that, the mechanism of coal gangue powder/brucite fiber composite modified asphalt was explored by the scanning electron microscopy(SEM) and infrared spectrum analyzer(IR). The results show that adding reasonable amount of coal gangue powder and brucite fiber can significantly improve the shear strength of asphalt mortar, adhesiveness and high temperature rheological properties as well as reduce the temperature sensitivity. Besides, the compound modifier can significantly improve the high-temperature stability, low-temperature crack resistance and water stability of asphalt mixture. The main factors influencing the performance of asphalt mixture are fiber content, specific surface area and average particle size of fillers. Coal gangue powder composite brucite fiber can form the space network reinforced structure in asphalt mixture. The enhancement, toughening and viscous effect can significantly improve the road performance of asphalt mixture.