| In recent years,with the advancement of the construction of "sponge cities" in China,the drainage asphalt mixture has received extensive attention.It has excellent functions such as anti-sliding,noise reduction,and suppression of water mist.However,its porous structure can also easily exacerbate the aging of high-viscosity asphalt,then thereby affect the service life of the drainage pavement.Montmorillonite(MMT)is a nanoclay with a special lamellar structure and has good barrier properties.Studies have shown that MMT as a modifier added to the asphalt not only can significantly improve its anti-aging properties,but also reduce the occurrence of rutting flow deformation and fatigue damage.Therefore,in this thesis,a new type of high viscosity asphalt was developed by MMT composite modification,and high temperature stability,low temperature crack resistance,fatigue resistance and anti aging performance under multiple environmental factors were studied,which lays a foundation for comprehensive understanding of the performance of the new modified asphalt.Firstly,two kinds of matrix asphalt,two kinds of high-viscosity modifiers and two types of organic montmorillonite(OMMT)were selected.Samples were prepared with the initial amount of modifier added,and the conventional indicators were used for comparative analysis.The microscopic characteristics of high viscosity asphalt with or without MMT were compared,so that Taizhou Zhonghai No.70 A Road asphalt,TPS modifiers and organic montmorillonite were selected to be suitable raw materials.Secondly,by comparing the conventional and rheological indexs of the MMT compound modified high-viscosity asphalt prepared with different feeding order,shear temperature ranges,rates and time.Comprehensive high and low temperature performance,the best preparation process of MMT compound modified high-viscosity asphalt is that add TPS high-viscosity modifier and then incorporate organic MMT,the shearing temperature is 180 ??190?,and shear rate is 4500rad/s and cutting time is 60min.Then,the thesis was tested conventional indexs of high viscosity asphalt with different content of OMMT and analyzed rheological indexs,such as 60? zero shear viscosity,rut factor,non-recoverable creep compliance,creep recovery rate thoes and fatigue factor.It was found that the addition of organic MMT can improve the high-temperature rutting resistance,low-temperature crack resistance and fatigue resistance of high-viscosity asphalt.After comprehensive analysis,the best modification of organic MMT in high-viscosity asphalt by the amount was determined to be 4%,its 60? zero shear viscosity is greater than 40000Pa·s,which meets the requirements of high-viscosity asphalt.The study also showed that the softening point may have errors in reflecting the high temperature rut resistance of high viscosity asphalt mixed with OMMT.So,it is suggested that the high temperature performance index based on rheological test should be used for evaluation.Under the condition of large stress,the high viscosity asphalt with a proper amount of OMMT shows obvious advantages of high temperature resistance to deformation and creep recovery,and the higher the temperature,the more obvious the advantage.Finally,the ratio analysis of the residual needle penetration ratio,the softening point increment and the residual ductility ratio of the MMT composite modified high viscosity asphalt and the ordinary high viscosity asphalt under the different aging conditions,as well as the variation of the rheological indexes of the non recoverable creep flexibility,the creep recovery rate and the fatigue factorfound that the combination of suitable amount of OMMT can improve the comprehensive performance of high-viscosity bitumen in resistance to thermal oxygen,water,and ultraviolet light.The research results can provide technical support for the further promotion of the drainage asphalt mixture and further contribute to the construction of eco-friendly pavements. |
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