Research And Development Of Lyotropic Dry High Viscous Asphalt Modifier And Its Performance Study

Wetting modified asphalt has problems such as agent segregation,decreased performance during storage,complex preparation and construction processes,high energy consumption and cost.However,dry high viscosity modifiers can be directly mixed with aggregates and matrix asphalt,with a simple process and low energy consumption.The performance and solubility of dry process high viscosity modifiers developed in China cannot fully meet the requirements for engineering use.Therefore,it is necessary to develop a dry high viscosity modifier with excellent road performance,good solubility,and low cost.This article preliminarily determines the raw materials and preparation process of the modifier;Study the influence of extrusion process on modifiers and modified asphalt,and determine the optimal extrusion process parameters;Analyze the modification effects of modifiers on different oil sources and types of matrix asphalt,and study the impact of aging on the road performance and dynamic mechanical properties of modified asphalt;Systematic evaluation of the self-healing performance of modified asphalt;Verify the road performance of high viscosity modified asphalt mixture.The main research conclusions are as follows:(1)This article preliminarily determines that the raw materials for high viscosity modifiers are: linear SBS,petroleum resin,isolation agent A,stabilizer A,antioxidant A,and cosolvent A;Based on the theory of polymer processing and molding and multiple on-site preparation experiences,the preparation process of this modifier includes mixing,extrusion,cooling,and shearing.The equipment used in the preparation process is a highspeed mixer,a single screw extruder,and a shearing machine;By using the results of orthogonal experiments and single index range analysis,the optimal ratio of raw materials for this modifier was ultimately determined;By analyzing the experimental results,the optimal dosage of this modifier in the matrix asphalt was determined;The extrusion process has a significant impact on the appearance,solubility,and road performance of the modifier,and the optimal appearance with solubility and performance is obtained.Based on the results of orthogonal experiments and the single index range analysis method,the weight of the impact of each extrusion parameter on the performance of modified asphalt and the optimal extrusion parameters of this modifier are ultimately determined.(2)The developed dry method high viscosity modifier has poor modification effect on KL matrix asphalt,and the high viscosity modified asphalt prepared from No.70 matrix asphalt has better performance.Based on the dynamic mechanical property test results before and after aging,the dynamic mechanical property,anti-aging performance and fatigue performance of dry high viscosity modified asphalt are better than RST modified asphalt,wet high viscosity modified asphalt(HV)and SBS modified asphalt.According to the Black plot analysis,it can be concluded that the internal homogeneity,solubility of modifier and matrix asphalt,and viscoelastic properties of dry high viscosity modified asphalt are slightly lower than those of wet high viscosity modified asphalt(HV).(3)The loading failure rate S and the complex Shear modulus growth rate H were determined as the self-healing evaluation indicators,and three intermittent linear amplitude tests(LAS)were designed(180s each time)to evaluate the self-healing property of modified asphalt.The test results show that the complex Shear modulus growth rate H of dry high viscosity modified asphalt is the highest before aging and after short-term aging,indicating that it has good self-healing performance;After long-term aging,the complex Shear modulus growth rate H of wet high viscosity modified asphalt(HV)is the highest,indicating that wet high viscosity modified asphalt(HV)has good self-healing performance after long-term aging.(4)The results of high-temperature rutting test,low-temperature bending beam test,immersion Marshall test,and freeze-thaw splitting test show that the prepared SMA-5high viscosity asphalt mixture meets the requirements of the specifications for road performance,and can be applied to special pavement structures such as drainage pavement,and has good high-temperature stability,low-temperature crack resistance,and water stability.