Micromechanical Modeling of Low-Temperature Viscoelastic Behavior of Crumb Rubber-Modified Bitumen

The addition of crumb rubber to bitumen for modifying certain properties and managing waste tires is a commonly adopted method worldwide. Typically, incorporating crumb rubber enhances bitumen's resistance to thermal cracking at low temperatures. Therefore, predicting the viscoelastic behavior of crumb rubber-modified bitumen is of significant importance. Given that the mixing process of crumb rubber with bitumen is physical in nature, it cannot be asserted that the resulting material is homogeneous. Consequently, in this study, a two-phase micromechanical model has been considered as a realistic approach for simulating the viscoelastic low-temperature behavior of crumb rubber-modified bitumen. To evaluate the low-temperature viscoelastic characteristics of both pure bitumen and crumb rubber-modified bitumen, the Bending Beam Rheometer (BBR) test was conducted at temperatures of -۶°C, -۱۲°C, -۱۸°C, and -۲۴°C. The primary outputs of this test include flexural creep stiffness, S(t) and the creep rate, m-value. Subsequently, by inputting the characteristics of pure bitumen and crumb rubber into the applied micromechanical model, the viscoelastic properties of crumb rubber-modified bitumen were calculated and compared with the experimental results. The findings demonstrate the model's satisfactory performance with an acceptable level of accuracy in predicting the low-temperature viscoelastic behavior of crumb rubber-modified bitumen samples.

کلیدواژه ها:

Bitumen ، Crumb Rubber ، Viscoelastic ، Micromechanical Model ، Low-Temperature