Semester of Graduation

Fall 2019

Degree

Master of Civil Engineering (MCE)

Department

Civil & Environmental Engineering

Document Type

Thesis

Abstract

An experimental study was conducted to characterize the chemical, molecular, and rheological properties of different asphalt emulsions including a newly introduced tire rubber modified asphalt emulsion. One tire rubber modified asphalt emulsion (CRS-2TR), two conventional emulsions (CRS-2 and CRS-2P), and one asphalt rubber binder (AC20-5TR) were evaluated. The differences in functional groups, chemical composition, and molecular weight distribution of the asphalt binder and emulsions under different aging conditions (Original, RTFO-aged, and PAV-aged) were evaluated by the Saturates, Aromatics, Resins and Asphaltenes (SARA) fractionation test, High-Pressure Gel Permeation Chromatography (HP-GPC), and Fourier Transform Infrared Spectroscopy (FTIR) test, respectively. Superpave Performance Grade (PG), Surface Performance Grade (SPG) and the Multiple Stress Creep Recovery (MSCR) test were also conducted to evaluate the rheological properties and rutting susceptibility of the binder residues.

Chemical and molecular characterization test results indicated that the tire rubber modified emulsion (CRS-2TR) had lower carbonyl indices (Ic=o) and colloidal instability indices (Ic) as compared to the conventional emulsions, indicating higher resistance to aging. Similar High-Molecular Weight (HMW) content compared to that of conventional asphalt emulsions was observed for CRS-2TR, indicating similar susceptibility to brittleness with age. On the other hand, rheological investigation results showed that the performance of CRS-2TR may be comparable with CRS-2P and is expected to perform better than CRS-2 against rutting, fatigue cracking, and thermal cracking. In addition, moisture susceptibility of the binder residues from the Bitumen Bond Strength (BBS) test showed that CRS-2TR had higher pull-off tensile strength in both dry and wet conditions as compared to CRS-2 and had statistically equivalent performance results as compared to CRS-2P.

Committee Chair

Elseifi, Mostafa

DOI

10.31390/gradschool_theses.5027

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