Reserch On Preparation And Key Evaluation Index Of High Viscosity Asphalt Modified By Crumb Rubber

Due to the special structure of the drainage pavement,the coarse aggregate accounts for a large amount,the void ratio is large,and the adhesion and durability requirements of the asphalt mixture are higher.Therefore,it is necessary to use high-viscosity asphalt to achieve higher adhesion.However,the high-viscosity asphalt modifiers currently used in the market have high costs and uneven modification effects.The application is subject to certain restrictions,and it is necessary to reduce costs and improve modification effects.Studies have shown that adding waste tire rubber powder particles to asphalt can not only effectively improve the viscosity and anti-aging properties of modified asphalt,but also reduce costs and turn waste into treasure,and alleviate the environmental pollution caused by improper disposal of waste tires.In view of this,this paper independently developed the waste rubber powder composite high-viscosity asphalt modifier,prepared the high-viscosity modified asphalt mixture and verified its performance,and combined the performance index of asphalt mixture with the technical index of asphalt binder for gray correlation analysis,The key research indicators of waste rubber powder composite modified high viscosity asphalt are proposed.Through the selection of raw materials,compounding of waste rubber powder,co-solvent and addition of tackifier,high-viscosity modified asphalt with good performance was prepared.By analyzing the regularity of penetration,softening point,ductility at 5℃,dynamic viscosity at 60℃ and viscosity and other conventional properties with the amount of modifier such as rubber powder,the results show that the The incorporation significantly improves the comprehensive performance of the asphalt after modification,and finally determines that the optimum dosage of modifier is 20% of waste rubber powder,5% of co-solvent,and 3% of viscosity increasing agent.A dynamic shear rheometer was used to conduct frequency scanning and temperature scanning tests on the waste rubber powder composite high-viscosity modified asphalt,and based on the principle of time-temperature equivalence and viscoelasticity,the temperature sensitivity of the modifier to the high-viscosity modified asphalt was studied.Influence of performance and high temperature viscoelasticity.The low-temperature bending beam rheometer was used to study the low-temperature rheological properties of the waste rubber powder composite modified high-viscosity asphalt.The Burgers model was used to further evaluate the low-temperature viscoelastic properties of the modified asphalt.And the microscopic morphology and modification mechanism of modified asphalt were analyzed by fluorescence microscope and infrared spectrum scanning test.The results show that through the study of the main curve viscoelastic properties and zero shear viscosity,it is found that the addition of waste rubber powder effectively improves the temperature-sensing performance of asphalt.After adding rubber powder and tackifier,the viscosity of modified asphalt is greatly increased.The high-low temperature performance of the waste rubber powder composite highviscosity modified asphalt is significantly improved compared to that before modification,and has better aging resistance.There is a certain physical and chemical reaction inside the waste rubber powder composite high-viscosity modified asphalt,So that asphalt has good compatibility between waste rubber powder,co-solvent and tackifier.The addition of co-solvent effectively improves the cross-linking effect between asphalt and rubber,which is an important reason for the performance improvement of modified asphalt.The waste rubber powder composite modified high-viscosity asphalt prepared above was used to prepare the drainage asphalt mixture.The asphalt mixture was first graded to determine the optimal asphalt-to-stone ratio.Two types of matrix asphalt were used as blank group and waste rubber powder modified asphalt was prepared as control group respectively.The high and low temperature performance and water stability of the prepared asphalt mixture were verified respectively,and the asphalt was evaluated and analyzed by the performance index of the mixture The quality of the material.Finally,the gray correlation analysis method is used to analyze the key evaluation indexes of the optimized asphalt binder,and the recommended values of the related indexes are proposed.The results of the study show that the asphalt mixture has good road performance and meets the requirements of the relevant specifications.It is recommended that the key asphalt parameters be 60 ℃ zero shear viscosity,rutting factor,viscosity and ductility and 5 ℃ ductility.