Determining the Optimum Content and Stirring Time of Emerging Dry Polymer for Asphalt Using Rotational Viscometer, Dynamic Shear Rheometer, and Atomic Force Microscopy

During the past decades, styrene-butadiene-styrene (SBS) triblock copolymer has been used to produce Polymer-Modified Asphalt (PMA) to make asphalt pavements more resistant to both rutting at a high temperature and cracking at a low temperature. However, the process of adding SBS copolymer to asphalt requires additional equipment such as high-shear mixing equipment, and the produced PMA is required to be stored in a separate tank. To overcome these limitations associated with the production handling, the pelletized SBS-based compound was developed. It can be added to the pugmill using a dry process together with asphalt and aggregates at the asphalt plant. The main objective of this study is to identify the proper melting time for the pelletized SBS-based compound in asphalt and to determine the optimum amount of the pelletized SBS-based compound. In this study, to characterize the pelletized SBS-based compound, atomic force microscopy (AFM), a dynamic shear rheometer (DSR), and a rotational viscometer (RV) were used. Based on the laboratory test results, optimum quantity and mixing time of pelletized SBS-based compound were identified.