Research on Asphalt Modification Technology of Packaging Waste (PE) II

2 experimental analysis and conclusion

2.1 Test data

Through the above mixing ratio tests, the modified asphalt is obtained, and the asphalt modified by the waste PE is tested. The test data are shown in Table 1.

2.2 Experimental data analysis

From the experimental data, it can be seen that the PE polymer modifier can significantly improve the performance of the asphalt. With the increase of the specific gravity of the PE plastic additive, the penetration of the modified asphalt decreases and the softening point increases.

An increase in the softening point means a significant reduction in the heat-stabilized fluidity of the modified matrix and a decrease in the molecular mobility of the matrix asphalt, which will affect the stability and creep properties of the blended material. This is due to the fact that when the polymer content is small and the pitch has high aromaticity, the polymer is soluble and the polymer pitch system is a single-phase system, and the polymer has little effect on the softening point. As the dose of the polymer continues to increase, phase separation occurs as the polymer phase is distributed in the bitumen in a continuous phase, where the polymer phase is swelled by the light components in the bitumen, resulting in the performance of the bitumen. Improve, slightly soften the point. As the polymer dose continues to increase, an interpenetrating network is formed, which appears as two continuous phases, and the softening point of the pitch increases rapidly with the polymer dose. When the polymer forms a network structure, the viscosity and elasticity of the modified asphalt are greatly increased. If the dose is larger, the asphalt phase becomes a discontinuous phase and is distributed in a polymer species in a continuous phase, thereby softening the increasing trend of the softening point.

The improved high temperature performance of Xing modified asphalt can be explained by the principle of swelling. PE melts like a resin at high temperatures and exhibits linear polymer performance above 130°C. At the same time, under the action of the light components of the asphalt, the two are allowed to infiltrate each other and a volume swell will occur. Swelling is an important part of the polymer modified asphalt. Through this step, the quality of the asphalt itself is directly changed. Combined with a good spatial three-dimensional network structure, the high temperature performance of the asphalt can be significantly improved. At the same time, PE is combined into a good spatial three-dimensional network structure in asphalt, which also leads to a decrease in penetration, and the asphalt becomes hard and the viscosity increases significantly (especially 70# asphalt).

With the increase of the content of added PE, some defects on the surface or inside of the material are induced by the stress concentration, and these holes develop fine marks, and when the deformation further develops, the molecular chain of orientation is straightened. When it breaks, it turns into micro-cracks. Due to the presence of fine particles of the PE modifier, the particles play a role of stress concentration, and the modifier particles cause a large number of fine lines or shear bands under external force stretching, so the room temperature crack resistance is reduced.

3 Conclusion

Through the above experimental data analysis, the conclusions are consistent with the theoretical analysis results, but there are still some deficiencies, such as: the method of collecting and classifying the active components of waste plastics; considering the improvement of highway performance and prolonging the life of the modified asphalt mixture Pavement construction projects develop corresponding economic policies, etc. These problems will be solved in future studies.

(Wen/Luo Guanglin and Fang Changqing Xi'an University of Technology)
"Packaging Project"