Temperature Sensitivity of Recycled Binders Containing Different Ages of RAP Binders: Fid-Bau Portal

Temperature Sensitivity of Recycled Binders Containing Different Ages of RAP Binders

Abinaya, L. / Nivitha, M. R. / Krishnan, J. Murali

Reclaimed asphalt pavement (RAP) materials constitute aged binders that warrant recycling to achieve the required rheological properties. For this purpose, recycling agents are added to the RAP materials to ‘soften’ the aged binder and meet the target rheological response. The rheological response of the recycled binders, particularly their sensitivity to temperature changes, predominantly contributes to pavement distress, such as permanent deformation and fatigue cracking. Therefore, it is necessary to quantify the variation in the rheological response of the recycled binders over a wide range of temperatures. Also, limited studies are available on the temperature sensitivity of recycled binders, especially concerning various ages of RAP binders. To address this, an unmodified binder was aged in a forced draft oven for 24 and 86 h to simulate two extents of aging. Recycling agents were added to the aged binders, and the binders were subjected to time sweep tests at temperatures ranging from 10 to 70 ℃. The Arrhenius plots of absolute shear viscosity and energy dissipation were used to calculate the activation energy, which is used as a measure of the temperature sensitivity of the binders. Results indicate that temperature sensitivity is greatly influenced by aging and the addition of recycling agents. Among the recycled binders with identical high-temperature performance grades, the recycled binder containing 86 h of oven aged binder exhibited lower temperature sensitivity. Notably, these differences in rheological responses between the recycled binders were most prominent at lower test temperatures of 10 to 30 ℃.