Multi-Scale Characteristics of Processing Viscosity of Rubberized Asphalt

The suspension system of rubberized asphalt causes high processing viscosity, leading to energy consumption, pollution and variation in engineering application. The pre-degradation of crumb rubber promoting the formation of colloid structure can significantly reduce the viscosity of rubberized asphalt. However, the viscosity as function of size of crumb rubber is still unclear. In this study, the effects of degradation degree, dosage of rubber and modifier type on the viscosity of degraded rubber modified asphalt, and the sensitivity of viscosity to shear rate and temperature were studied by analyzing the multi- structure of rubberized asphalts including its composition, morphology and molecular chain. Results show that the preprocessing (degradation) of rubber improves its dispersion in asphalt, increases the content of sol in the matrix, and decreases the content and size of gel particles, leading to the decreased viscosity with the increase of the degradation degree of rubber. Moreover, the viscosity of rubberized asphalt increases with the increase of the content of rubber. As the content is 35%, the gel particles contact with each other and form a net, the viscosity sharply rises. The degraded rubber modified asphalt has obvious rheological shear sensitivity and relatively weakened temperature sensitivity. In addition, the deeply degraded rubber/SBS hybrid modified asphalt has high shear sensitivity and temperature sensitivity. Accordingly, the processibility of rubberized asphalt could be improved by the combination of heating and increasing shear rate (vibration frequency) in engineering applications. © 2024 Sichuan University. All rights reserved.