Effect of Dissolved Species from Crumb-Rubber Modifier on Micromechanical Properties of Asphalt Binder

This study presents a correlation between the crumb-rubber modifier\u27s (CRM) released components into the crumb-rubber-modified asphalt (CRMA) and the developed micro-mechanical properties of a thin asphalt layer. This simulates the behavior of thin asphalt layers formed around the aggregate during mixing of hot-mix asphalt (HMA). This study provides a link between the modified asphalt\u27s change in intrinsic materials properties (elastic modulus and hardness) and the CRM released components. The CRM dissolution and component release were calculated by performing dissolution tests and thermo-gravimetric analysis (TGA) on the extracted CRM particles after interaction with asphalt. The utilization of TGA tests confirmed that the change in the CRMA\u27s hardness and elastic modulus was dependant on the dissolution and/or release of CRM components. It was found that the enhancement of CRMA micromechanical properties is attributable to the release of most of the CRM natural and synthetic rubber components under specific interaction conditions. At the early stage of interaction time, minimal release in CRM components results in minor enhancement in the CRMA hardness and elastic modulus. Upon the increase of interaction time (up to 8 hours), major enhancement is observed as a result of the release of most of the CRM components