Effect of Blending Conditions on the Rheological Properties of Asphalt modified by Reactive Ethylene Terpolymer and Polyphosphoric Acid
Date
2021-06-29
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Abstract
Polymer modification has become the common practice of the paving industry for the enhancement of thermo-rheological and engineering properties of asphalt materials. Despite considerable research in this area, the preparation of polymer-modified asphalt is still mostly done on a trial-and-error basis. In order to optimize the production technology of polymer-modified asphalt, this thesis studies the effects of the blending temperature, the concentration of polyphosphoric acid, and the order of addition of the modifiers on the properties of ternary blends Elvaloy 5160/asphalt/polyphosphoric acid. The rheological properties of asphalts were investigated through Superpave binder specification as well as dynamic mechanical analysis, and Fourier-transform infrared spectroscopy (FTIR). The results of testing using Superpave binder specification showed that Elvaloy 5160 enhanced the resistance of modified asphalt to permanent deformation at high temperatures without significantly affecting the performance at low service temperature. The addition of polyphosphoric acid (PPA) to asphalt modified by Elvaloy 5160 led to higher permanent deformation resistance as well as enhancing the resistance to thermo-oxidative ageing simulated by the Rolling Thin Film Oven Test (RTFOT). This was attributed to the double contribution of Elvaloy reaction with asphaltenes and the effect of PPA on the distribution of asphaltenes that increases the viscosity of the asphalt, resulting in a stiffer material. In general, the dynamic mechanical analysis showed that the blending temperatures played a significant role in the development of the internal structure and the relaxation-deformation properties of ternary asphalt materials. It appears that ternary blends Elvaloy 5160/asphalt/polyphosphoric acid favored lower blending temperatures. The order of addition of the modifiers greatly affected the properties of modified asphalt blended at 160ºC and 180ºC. Adding first PPA to the asphalt followed by Elvaloy resulted in a higher rutting resistance.
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Keywords
Polymer modified asphalt, Rheology, Blending conditions
Citation
Rios Carreno, L. C. (2021). Effect of Blending Conditions on the Rheological Properties of Asphalt modified by Reactive Ethylene Terpolymer and Polyphosphoric Acid (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.