Rheological properties assessment and micro-mechanism of asphalt modified by activated coal gangue
To promote the efficient,high-value and construction-oriented utilization of waste coal gangue,and to achieve synergistic,safe,and resource-sustainable development in the mining and transportation sectors,the high specific surface area and strong adsorption properties of activated coal gangue-based materials were explored. Firstly,three treatment processes of high-temperature calcination,wet alkaline dissolution and dry alkaline fusion were applied to coal gangue powder,resulting in three types of activated powders and four modified asphalts. Secondly,the microstructure of each treated coal gangue powder were investigated through microscopic analysis. Finally,the rheological properties and modification mechanisms of the coal gangue-based modified asphalts were evaluated. The results show that high-temperature calcination causes fracturing of the layered structure in coal gangue,resulting in a loose,granular form. With wet alkaline dissolution,substantial gel materials form on the coal gangue surface,increasing specific surface area by 15.7 times. Dry alkaline fusion creates a porous skeletal structure,enhancing specific surface area by 25.0 times. Compared to base asphalt,the rutting factor and non-recoverable creep compliance of asphalt modified with coal gangue activated by wet alkaline dissolution and dry alkaline fusion methods show varying degrees of improvement. This indicates that coal gangue-based materials can significantly enhance the high-temperature rheological properties of asphalt. At-18 ℃,the coal gangue modified asphalt,which is activated by high-temperature calcination,exhibits superior low-temperature performance. The increase in free energy of the coal gangue-modified asphalt suggests strong interfacial adhesion between the materials,and it is primarily driven by physical adsorption and molecular interactions. The porous structure of the activated coal gangue adsorbs light components,forming a "structured asphalt" within the asphalt matrix. This generates spatial constraints that limit the movement of asphalt macromolecular chains,thereby improving the high-temperature stability of the asphalt.
万方数据
维普
