Preparation And Properties Of Polyolefin/Waste Rubber Powder Composite Modified Asphalt

With the continuous development of China’s industry,the black pollution of automobile waste tires and the white pollution of plastics are becoming more and more serious.On the one hand,the study of polyolefin/waste rubber powder composite modification can make rational use of waste resources and turn waste into treasure,on the other hand,it can improve the performance of asphalt.In order to obtain the best preparation process of composite modified asphalt,through the analysis of three indexes,Brinell viscosity test results and orthogonal test analysis,the preparation process of HDPE/waste rubber powder composite modified asphalt and the optimal dosage of HDPE and waste rubber powder modifier are determined to prepare HDPE/waste rubber powder composite high viscosity modified asphalt.It is concluded that the best preparation process of HDPE/waste rubber powder composite modified asphalt is shear speed 6000r/min,shear time 60min,shear temperature 180℃,the best ratio of modifier HDPE is 3%and waste rubber powder is 15%.In order to improve the compatibility of composite modified asphalt,five groups of compatibility improvement schemes are designed to evaluate the compatibility of modified asphalt through three methods.It is concluded that nano zinc oxide and aromatic oil can promote the swelling and diffusion of rubber powder;Maleic anhydride and EVA are helpful to improve the compatibility between HDPE and asphalt;The Jnr evaluation index and the segregation rate evaluation index show that the storage stability of each group of modified asphalt is in good order,which is consistent with the phenomenon of thick and thin crust,The conclusions of three isolation evaluation methods are consistent.In order to study the influence of different types of polyolefins on the performance of composite modified asphalt,two groups of schemes of low-density polyethylene LDPE and copolymerized polypropylene PP-B are added to compare their differences with high-density polyethylene HDPE Composite Modified Asphalt in high-temperature performance,fatigue performance and low-temperature performance.It is concluded that polyolefin/waste rubber powder composite modified asphalt has higher PG high temperature grade than rubber powder modified asphalt,and HDPE/waste rubber powder composite modified asphalt and PP-B/waste rubber powder composite modified asphalt show better high temperature performance;LDPE/waste rubber powder composite modified asphalt shows better low-temperature crack resistance and fatigue performance.It is found that the physical and chemical changes of functional groups are mainly plane vibration and chemical reaction,and the chemical changes of functional groups are mainly plane vibration and blending.The difference between the dispersion of modifier and the particle size of modifier in the preparation of modified asphalt was found by fluorescence microscope.The diameter of swelling waste rubber powder particles in asphalt is 10 μm-20 μm,LDPE and nano zinc oxide particles have small diameters and are easy to gather at the cracks on the asphalt surface.HDPE and PP-B particles are relatively larger than polymerization particles,and their dispersion is not as uniform as LDPE.