| Asphalt is a critical component of road materials,and its performance directly affects the durability and stability of roads.However,with the increasing and diversifying traffic loads,the traditional SBS-modified asphalt can no longer meet the performance requirements of road materials.To enhance asphalt performance,nanomaterials are widely used for asphalt modification because of their special properties such as small size effect,quantum size effect and surface effect.Meanwhile,fiber incorporation is also an effective modification method.In this study,nano-AAT(American Advanced Technology)and ceramic fibers are used as modifiers to give full play to the advantages of nanomaterials and fiber materials through composite modification,forming a kind of superposition effect to obtain a better modification effect.Firstly,nano-AAT modified asphalt with different SBS admixtures was prepared and the effects of nano-AAT modifiers with different SBS admixtures on the properties of the matrix asphalt were investigated by basic performance tests(three major index tests and viscosity tests),temperature scan tests and low temperature bending beam rheological tests.The results showed that the needle penetration of nano-AAT modified asphalt decreased and the softening point,ductility and viscosity increased with the increase of SBS admixture.In addition,the nano-AAT modified asphalt has good rutting resistance at high temperature,smaller stiffness modulus and greater creep rate at low temperature,which also indicates better low temperature performance.Secondly,for nano-AAT modified asphalt,nano-AAT/ceramic fiber composite modified asphalt was prepared by mixing different proportions of ceramic fibers.The effect of ceramic fiber on the performance of nano-AAT modified asphalt was investigated by basic performance test,temperature scan test,multiple stress creep recovery test,low temperature bending beam rheology test,bond strength test and contact angle test,and the modification mechanism was analyzed by Fourier infrared transform spectroscopy test and atomic force microscopy test.The results showed that the needle penetration and ductility of the composite modified asphalt decreased and the softening point and viscosity increased with the increase of ceramic fiber doping.The composite modified asphalt showed excellent high-temperature deformation resistance,which was demonstrated under different temperature and frequency conditions,as well as under loading at two stress levels of 0.1kpa and 3.2kpa.The low temperature performance was somewhat weakened compared to the nano-AAT modified asphalt.The modification process of both modifiers on the matrix asphalt was found to be physically modified by infrared spectroscopy and microscopic morphology,which also dispersed uniformly in the asphalt,forming a more compact nanocomposite structure and fiber structure asphalt.The composite modified asphalt exhibited better adhesion properties than the nano-AAT,SBS and matrix asphalt.Finally,in this study,SMA-13 gradation was selected for asphalt mixture preparation,and the effect of nano-AAT/ceramic fiber composite modified asphalt on the road performance of the mixture was analyzed.The results showed that the composite modified asphalt mix showed superior performance in terms of high temperature stability,low temperature crack resistance and water stability performance compared with the conventional SBS modified asphalt.This indicates that composite modification with nanomaterials and fiber materials is an effective method to significantly improve the performance of asphalt mixtures,thus better meeting the requirements of road engineering for material performance.In summary,the nano-AAT/ceramic fiber composite modified asphalt prepared in this study showed significant improvement in overall performance compared with SBS modified asphalt and base asphalt.It shows its great potential for application in asphalt pavement construction,which is of positive significance for the development of highquality asphalt pavement projects. |
