RESUMO
The aim of this study is to propose a desulfurized rubber powder / styrene butadiene styrene (DRP/SBS) composite modified asphalt technology by combining the advantages of DRP and SBS. This reduces the production cost of modified asphalt and improves the performance of asphalt. In this paper, orthogonal tests were used to optimize preparation process parameters of DRP/SBS composite modified asphalt. And the physicochemical properties, modification mechanism of composite modified asphalt had been thoroughly studied. Subsequently, the results showed that the optimum content of DRP and SBS modifiers are 25 % and 2 %, respectively. The suitable preparation process is to add SBS first, then DRP, while shearing at 5000 r/min for 50 min. In addition, DRP/SBS composite modified asphalt has better high-temperature performance, viscosity-temperature characteristics, aging resistance, and storage stability. Meanwhile, the storage stability of the composite modified asphalt was verified by fluorescence microscopy test. Through the Fourier transform infrared spectroscopy test, it was observed that the composite modified asphalt modification process is a compatible and stable modification of physical and chemical coexistence. Overall, the composite modification method achieves recycling of waste tires while improving pavement performance, thus promoting the sustainability of pavement.
RESUMO
Due to the high viscosity, rubber asphalt displays poor construction workability, which ultimately compromises the comfort and safety of pavement. In this study, specified control variates were used to study the effect of the waste engine oil (WEO) addition sequence on the properties of rubber asphalt while ensuring the consistency of other preparation parameters. Initially, in order to evaluate their compatibility, the storage stability and aging properties of the three groups of samples were determined. The variation of asphalt viscosity was then analyzed using a low-field nuclear magnetic resonance (LF-NMR) test, by predicting the fluidity of each sample. Subsequently, the results showed that the rubber asphalt prepared by premixing WEO and crumb rubber (CR) had the best properties of low temperature, compatibility, and fluidity. On this basis, the effects of WEO content, shear rate, shear temperature, and shear time on the properties of low viscosity rubber asphalt were investigated separately through response surface methodology (RSM). Quantitative data from the basic performance experiment were used to fit the high precision regression equation, thereby correlating a more precise level of factors with experimental results. The response surface model prediction analysis showed that the optimal preparation parameters of the low viscosity rubber asphalt were 60 min shear time, 180 °C shear temperature, and 5000 r/min shear rate. Simultaneously, the addition of 3.5% of WEO showed great potential as an asphalt viscosity reducer. Ultimately, this study provides an accurate method for determining the optimum preparation parameters of asphalt.
Assuntos
Temperatura Baixa , Borracha , ViscosidadeRESUMO
The typical treatment of waste plastics has become a global environmental problem. In light of recent developments, waste plastics used as asphalt modifiers offer an efficient approach to solve this problem. This paper studied the effects of three kinds of waste plastic-modified asphalts (WPMA), with polypropylene (PP), polyethylene (PE) and ethylene-vinyl acetate copolymer (EVA) as their respective modifiers, on the conventional asphalt performance. Furthermore, an orthogonal experimental design (OED) was used to determine the preparation parameters of WPMA. Thereafter, thermogravimetric-differential scanning calorimetry (TG-DSC) and Fourier transform infrared spectroscopy (FTIR) were employed to expound the mechanism of WPMA. It was then subsequently ascertained that the optimum preparation parameters of PP-modified asphalt (PPMA) and PE-modified asphalt (PEMA) were 170 °C, 3000 rpm, and 30 min, while the optimum preparation parameters of EVA-modified asphalt (EVAMA) were 180 °C, 3000 rpm, and 30 min. In addition, WPMA displayed better high-temperature performance and are inherently more suitable for pavement in high-temperature regions. Ultimately, this study will effectively solve the disposal of waste plastic and promote the research and application of WPMA in the future.
