Fundamental Properties of Asphalts and Modified Asphalts, III

PA - Carbonyl total peak ht. (1700 cm-1)
1.400
1.300
1.200
1.100
1.000
0.900
0.800
0.700
0.600
0.500
y = 2.42x + 0.53
R 2 = 0.81
0.400
0.000 0.050 0.100 0.150 0.200 0.250 0.300 0.350
Liquid Cell - Carbonyl corr. peak ht. (1700 cm-1)
Figure 2-2.2.8. Comparison SHRP asphalts – Carbonyl peak height at 1700 cm -1 , PA vs. Liquid
cell, without unaged or RTFO asphalts. Note: Liquid cell carbonyl represents the corrected peak
height, and PA carbonyl represents the total peak height.
SHRP RD aggregate (limestone, CaCO3)
PA spectra of RD (limestone) aggregate at several OPD velocities are presented in figure 2-2.2.9.
Spectral artifacts seem evident at lower OPD velocity, particularly at 0.1 cm/sec, where the
broad absorbance band at 1430 cm -1 appears to have sharp side lobes not corrected by the strong
apodization function selected for this analysis. Also, the broad absorption at 1430 cm -1 appears
to be inverted.
Limestone is a sedimentary rock composed of more than 50% carbonate minerals. There are two
common, naturally occurring polymorphs of calcium carbonate (CaCO3): aragonite and calcite.
Aragonite’s crystal lattice differs from that of calcite, resulting in a different crystal shape. The
bands at 713 cm -1 , 876 cm -1 , 1075 cm -1 , and 1430 cm -1 , which appear most distinct in the top
spectrum, represent carbonate vibrations.
The bands at about 1800 cm -1 , 2510 cm -1 and 2900 cm -1 are overtone and combination bands
[Logodi et al. 2001; Vassallo et al. 1992]. The lack of a sharp band around 1070–1080 cm -1 in
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