Investigation on the Effect of Crumb Rubber Modification on Non-linear Viscoelastic Characteristics of Asphalt Binder

One of the most important expectations of asphalt binder additives consumers is a reasonable change in rheological and mechanical behavior of original asphalt binder. Crumb rubber is a well-known modifier commonly used to enhance rutting resistance, fatigue behavior and thermal cracking at low temperatures of neat asphalt binder. Generally, rheological and mechanical changes of neat asphalt binder in presence of different types of additives are investigated within linear viscoelastic range. However, evaluating non-linear behavior of neat and modified asphalt binders at higher temperatures, higher stress levels and higher loading rates is important as well. In this study, implementing dynamic shear rheometer (DSR), the creep – recovery test was performed to evaluate rheological behavior within non-linear viscoelastic range of asphalt binders modified with three different dosages of crumb rubber including 10, 15 and 20%. The experimental results were analyzed based on simple theoretical related to non-linear viscoelastic behavior as well as generalized non-linear fractional viscoelastic model. The analysis showed that adding crumb rubber to neat asphalt binder causes an increasing
non-linear behavior which means improvement of rutting resistance at 40 degree of centigrade. Also, increasing the dosage of crumb rubber amplifies this trend.