TY - JOUR
T1 - Study of phase behavior of epoxy asphalt binders using differential scanning calorimetry
AU - Apostolidis, Panos
AU - Elwardany, Michael
AU - Andriescu, Adrian
AU - Mensching, David J.
AU - Youtcheff, Jack
PY - 2023
Y1 - 2023
N2 - Glass transition parameters can be used to study the miscibility, or lack of it, in polymer-modified asphalt binders. In this study, the contribution of thermodynamics of mixing to glass transition was quantitatively assessed in a differential scanning calorimeter for four asphalt binders partially and fully replaced by an epoxy system. The values of heat capacity (Cp) and, subsequently the glass transition temperature (Tg) of all binders were determined to quantify the miscibility based on the entropic changes. Emphasis was also given to examining the enthalpy of mixing as a function of epoxy system composition during curing to ensure that these binders were completely crosslinked for further analyses. In all cases, the positive deviations of the measured Tg of epoxy-modified asphalt binders (Tg,mix) obtained from the ideal mixing rule led to negative values of the entropy of mixing (ΔSmixc), dictating the presence of internal repulsive forces between the asphalt and epoxy components. Softer binders were associated with binders of low deviations of Tg,mix values from the ideal mixing rule. Lastly, the partial replacement of asphalt binders by the epoxy system increased the Tg and decreased the amount of ΔSmixc, and such performance imposes the formation of immiscible products.
AB - Glass transition parameters can be used to study the miscibility, or lack of it, in polymer-modified asphalt binders. In this study, the contribution of thermodynamics of mixing to glass transition was quantitatively assessed in a differential scanning calorimeter for four asphalt binders partially and fully replaced by an epoxy system. The values of heat capacity (Cp) and, subsequently the glass transition temperature (Tg) of all binders were determined to quantify the miscibility based on the entropic changes. Emphasis was also given to examining the enthalpy of mixing as a function of epoxy system composition during curing to ensure that these binders were completely crosslinked for further analyses. In all cases, the positive deviations of the measured Tg of epoxy-modified asphalt binders (Tg,mix) obtained from the ideal mixing rule led to negative values of the entropy of mixing (ΔSmixc), dictating the presence of internal repulsive forces between the asphalt and epoxy components. Softer binders were associated with binders of low deviations of Tg,mix values from the ideal mixing rule. Lastly, the partial replacement of asphalt binders by the epoxy system increased the Tg and decreased the amount of ΔSmixc, and such performance imposes the formation of immiscible products.
KW - Differential scanning calorimetry
KW - Glass transition
KW - Miscibility
KW - Phase behavior
UR - http://www.scopus.com/inward/record.url?scp=85147540436&partnerID=8YFLogxK
U2 - 10.1016/j.conbuildmat.2023.130566
DO - 10.1016/j.conbuildmat.2023.130566
M3 - Article
AN - SCOPUS:85147540436
SN - 0950-0618
VL - 369
JO - Construction and Building Materials
JF - Construction and Building Materials
M1 - 130566
ER -