Evaluation of healing in asphalt binders using dynamic shear rheometer and molecular modeling techniques

Evaluation of Healing in Asphalt Binders Using Dynamic Shear Rheometer and Molecular Modeling Techniques. (August 2008) Ramamohan Reddy Bommavaram, B.Tech., Indian Institute of Technology Madras Chair of Advisory Committee: Dr. Dallas Little A self-healing material has the inherent ability to partially reverse damage such as crack formation that might have occurred during its service. Significant evidence exists in the literature to indicate that asphalt binder is a self-healing material. It is also well known that healing has a substantial affect on the performance of asphalt mixtures and consequently on the serviceable life of asphalt pavements. For example, shift factors from laboratory experimental data to field observed data show that laboratory data underpredict field observations. There is a need to understand the mechanisms that are responsible for healing in asphalt binders as well as to develop test methods that can be used to determine properties related to these mechanisms. This thesis presents details and findings from a two-part study that addresses each one of these two aspects. In the first part of this study, a test method based on the use of a Dynamic Shear Rheometer (DSR) was developed to determine the parameters of characteristic healing function of asphalt binders. In the second part of this study, Molecular Modeling (MM) techniques were used to determine the interrelationship between molecular structure, surface free energy, self diffusivity, and other healing properties of asphalt binders.