Characterization of Rubberized Binders with Wax Additives
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Crumb rubber is widely used as an environment-friendly material in asphalt industry to improve pavement performance properties. Warm mixture asphalt (WMA) refers to the technologies which allow a substantial reduction of mixing and compaction temperatures of asphalt mixtures through decreasing the viscosity of asphalt binders. In general, the crumb rubber modified (CRM) asphalt mixes require higher temperatures compared to conventional hot mix asphalt (HMA). However, if the technologies of WMA are incorporated, it is predicted to reduce the mixing and compaction temperatures of rubberized asphalt mixtures. For utilization of rubberized mixes in WMA industry, it is needed to investigate the properties of CRM binders with warm additives depending on CRM contents, additive types, aging states, and other experiment variables.
This research investigated CRM binders with wax warm additives, and the objectives included: 1) quantifying viscosity changes dependent upon mixing temperature and hauling period through Rotational viscometer test; 2) evaluating the effect of blending time on viscosity; 3) investigating the performance properties of recycled aged CRM binders containing wax additives through Superpave binder tests; 4) evaluating the microstructural properties using an environmental scanning electron microscope (ESEM) and an atomic force microscopy (AFM).
The following conclusions were drawn based on the comprehensive laboratory investigation: 1) crumb rubber contents and wax types were found to have significantinfluence on the viscosity properties of CRM binders; 2) CRM binder with wax additive (LEADCAP) showed better rutting and cracking resistance compared to the control CRM binder for all aging states; 3) the wax additive in recycled CRM binder is observed to play an important role in binder properties even after subjecting to long-term aging processes; 4) the microstructures on morphology images seemed to have a good relation with the engineering properties of warm CRM binders.
CitationKim, H. (2016). Characterization of rubberized binders with wax additives (Unpublished dissertation). Texas State University, San Marcos, Texas.