Characterization Of Simple And Complex Crumb Rubber Modified Binders Final Report

摘要

This research focused on the evaluation of using crumb rubber modifier (CRM) in asphalt binders. The increasing usage of CRM in asphalt pavements requires a better understanding of the physical, chemical, and rheological properties of CRM so that its performance in the field can be more accurately predicted. The existing literature regarding CRM in asphalt binders has been focused on using either conventional binder testing procedures or the Superpave binder testing protocol. It is believed that Superpave binder specifications cannot be extended to all modified binders, since certain simplifications are used in the current specification that cannot estimate their contribution to pavement performance under different traffic and pavement structure conditions. Therefore the benefits of using crumb rubber for modification of asphalt needs more detailed evaluation using an extended set of testing methods. This report shows the results of the binder testing and analysis of these results to quantify the effects of size and concentration of CRM on critical binder properties related to construction and performance of HMA in pavements. The evaluation was conducted by measuring the change in performance-related properties of the selected asphalt binders as a result of mixing various levels of CRM content and particle with asphalts. Testing was conducted at different temperatures, testing frequencies, and strain conditions using methods recently developed as part of the NCHRP 9-10 project (Superpave Protocols for Asphalt Binders). Statistical analysis was used to develop models that predict the nature of effects on the performance-related properties of asphalts and that can quantify the role of different variables.