Chemical, physical, and thermodynamic properties of neat and polymer-modified asphalt binders

Asphalt was modified with four different polymers to investigate the benefits of polymer modification. The modifiers studied were styrene-butadiene rubber, Elvaloy AM, recycled crumb rubber, and ethylene vinyl acetate. A mixing procedure was developed for each modifier based on improvement in the rheological properties of the blend. A number of physical properties were investigated to determine the benefit of polymer modification. Polymer modification improved high temperature properties and did not affect low temperature properties.;Fourier Transform Infrared Spectroscopy and Gel-Permeation Chromatography were used to fingerprint the modified binders. Phenomenological models were developed for SBR and CRM rheological properties. The properties of SBR are a combination of two phenomena: percolation and network formation. The properties of CRM are a result of simple two-phase dispersed mixing. Laser scanning and environmental scanning electron microscopy were used to verify the models. The applicability of the SHRP performance based specifications for modified asphalts was investigated.