The Development of a New Thermoplastic Elastomer (TPE)-Modified Asphalt

The use of (recycled) plastics and (waste) vulcanized rubber powder is the main polymer of raw materials, and composite organic additives are selected to fully combine with asphalt components. The physical and chemical reactions between different components are completed in dynamic mixing, establishing a morphology structure similar to thermoplastic elastomers (TPEs), and a thermoplastic highly asphaltized alloy material. TPE-modified asphalt not only significantly improves the high-temperature stability of the base asphalt, but also has the social and economic value of rational utilization of resources and turning waste into treasure. There are very few studies on the preparation of modified high-viscosity asphalt formulations using rubber and plastic as modifiers. In this study, rubber, plastic, and plasticizers were added to the base asphalt, and the TPE modifier formulations were developed through the research of new TPE modifier series and functional formulations, preparation process, and its modified asphalt properties. Meanwhile, the preparation method of the rubber–plastic alloy modifier was determined. The performance of the TPE-modified asphalt was verified through performance verification tests to evaluate the modification effect of the modifier on the base asphalt. The test results showed that the penetration, softening point, ductility, and viscosity indexes of the TPE-modified asphalt developed through the proposed formulation, and it met the specification requirements for high-viscosity modified asphalt. Rubber and plastic modifiers significantly improved the high-temperature stability of the base asphalt. In addition, the rubber–plastic modifier had a significant tackifying effect, with a dynamic viscosity of 60 °C and a Brinell rotational viscosity much greater than asphalt and rubber asphalt. The microscopic mechanism of the newly developed TPE-modified asphalt was analyzed by fluorescence microanalysis. The results showed that the rubber–plastic modifier fully swelled in the asphalt and was uniformly dispersed in the asphalt as a floc. The network structure of activated waste rubber powder-modified asphalt was more uniform and dense, resulting in good performance of the modified asphalt, and stable storage of modified asphalt was obtained. Through appropriate formulation, the comprehensive performance of the TPE-modified asphalt obtained met the requirements of pavement application and construction, providing a good theoretical basis for promoting TPE-modified asphalt.