Title page for ETD etd-06082009-115927


Type of Document Master's Thesis
Author Sellers, Brent Harper
Author's Email Address bselle4@tigers.lsu.edu
URN etd-06082009-115927
Title Characterization and Transitions of Asphalt Cement Composite Materials
Degree Master of Science (M.S.)
Department Chemistry
Advisory Committee
Advisor Name Title
William H. Daly Committee Chair
Ioan I. Negulescu Committee Member
Louay N. Mohammad Committee Member
William E. Crowe Committee Member
Huangen Ding Dean's Representative
Keywords
  • asphalt cement
Date of Defense 2009-04-07
Availability unrestricted
Abstract
Blends of a PG 64-22 asphalt with a range of load levels (0.2 — 20 wt %) of

Sasobit® wax and a single loading of 2 wt % Elvaloy AM® were prepared and

characterized. Sasobit® wax is a high molecular weight paraffinic wax produced

commercially through the Fischer-Tropsch process. Elvaloy AM® is a reactive elastic

terpolymer, comprised of ethylene, butyl acrylate and glycidyl methacrylate monomeric

units. The blends were analyzed by gel permeation chromatography (GPC), differential

scanning calorimetry (DSC), x-ray diffraction, epifluorescence microscopy, scanning

laser confocal microscopy, and dynamic shear rheology. Sasobit (1 wt %) composite

material showed little difference in aging characteristics with respect to the aging

chromatograms of the un-modified asphalt cement. Aging of Elvaloy (2 wt %) composite

material leads to increased concentrations of asphaltene and asphaltene aggregate

components at a greater rate than that observed with the Sasobit composites and

unmodified asphalt cement. Analysis of DSC heating curve enthalpies revealed that

Sasobit composites at loadings above 4% that the Sasobit was completely crystalline.

X-ray diffraction confirmed that ambient temperature Sasobit composite samples

maintained their crystalline form down to the level of 0.2 wt % loading. Evidence for the

additives presence could be seen within the asphalt matrix through epifluorescence and

scanning laser confocal microscopy imaging of each of the composite systems

investigated. Bright point-sources of fluorescence, most easily picked out in the Elvaloy

(2 wt %) composite images, are believed to be asphaltene micelles. Evidence of

improved G* performance in both Sasobit and Elvaloy composite master curves with

respect to the neat asphalt cement master curves is presented. The dynamic viscosity

data at 1 Hz shows that original and TFOT data doesn’t clearly differentiate between

Sasobit composites and neat asphalt cement until after PAV aging. At that stage the

Sasobit composite shows truly linear dynamic viscosity response suggesting that

Sasobit inclusion leads to better dispersion of the viscosity building asphaltene

component throughout the asphalt cement. It is believed that the Elvaloy AM composite

experienced some degree of crosslinking during aging and this is most evident following

the PAV aging in the rheological data.

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