Research On The Properties Of Asphalts Modified By Waste Rubber Powder And Reclaimed Low Density Polyethylene

The rubber modifier is able to improve asphalts' overall properties, it can not only improve asphalts' ability to resist deformation at high temperatures, but also can remarkably increase asphalts' low temperature flexibility; However, as for the polyethylene modifier, even though it can significantly improve the hardness of asphalt, reducing the pavements' deformation caused by vehicle loads at high temperatures, it has limited effect on the improvement of asphalts' low temperature properties. Considering the respective effects of rubber and polyethylene on asphalts' properties, and the increasingly serious environmental problems created by waste polymers, in this paper, waste tire rubber powder(WTR) and reclaimed low density polyethylene(RPE) were combined to produce WTR/RPE modified asphalts. During the research, the processing condition to produce WTR/RPE modified asphalts, the WTR/RPE modified asphalts' performance and mechanism were studied using test methods. The main contents of this paper are as follows:Firstly, the effects of processing conditions on WTR/RPE modified asphalts' conventional properties(including penetration, softening point and ductility) were investigated using orthogonal test method, the results indicates that the processing conditions have important effects on the WTR/RPE modified asphalts' properties. What's more, through direct analysis, the effects of processing condition's parameters on the properties of WTR/RPE modified asphalts, and the optimal processing condition to produce WTR/RPE modified asphalts were indentified.Secondly, the WTR/RPE modified asphalt's performance was evaluated based on the asphalts' conventional properties, rheological properties and aging properties. The results show that WTR and RPE formed a continuous polymer network in the WTR/RPE modified asphalts, and greatly improved asphalts' high temperature performance and anti-aging ability; however, the compound modification effect of WTR and RPE on asphalts' low temperature properties is controversial, because compared with the base asphalt, even though the WTR/RPE modified asphalts have low values of creep stiffness, they also have weakened ability to disperse stress.Finally, the mechanism of interection between WTR/RPE and asphalt was determined using micro-analysis methods, including fluorescence microscopy, infrared spectroscopy, thermogravimetry and differential scanning calorimetry analysis. The results indicate that the asphalt's compound modification using WTR and RPE is a combination of both physical and chemical process; After added into the base asphalt, WTR and RPE adhered to each other, and formed a continuous polymer network in the asphalt phase, not only making the RPE particle smaller and increasing the degree of RPE's dispersion, but also improving the compatibility between RPE and asphalt phase; What's more, from a thermodynamic perspective, after the asphalt was modified by WTR and RPE, a more thermo-stable and thermo-uniform mixture was achieved.