Fundamental Properties of Asphalts and Modified Asphalts, III

• LTA1 (long term aging Level 1): The loose mix aging procedure was the same as STA
except the compacted specimen (75-mm diameter by approximately 120-mm tall) was
conditioned at 85˚C for two days.
• LTA2 (long term aging Level 1): The loose mix aging procedure was the same as STA
except the compacted specimen (75-mm diameter by approximately 120-mm tall) was
conditioned at 85˚C for four days.
• LTA3 (long term aging Level 1): The loose mix aging procedure was the same as STA
except the compacted specimen (75-mm diameter by approximately 120-mm tall) was
conditioned at 85˚C for eight days.
In this analysis, the effects of short- and long-term laboratory aging were measured by first
splitting open the STA and LTA3 cores and removing small samples of mastic from the edge and
center of the open face of the cores as illustrated in figure 2-2.2.16. Asphalt from the small
mastic samples was recovered and evaluated by FTIR
Figure 2-2.2.16. Core face (typical) - mastic sample locations (STA and LTA3).
The FTIR analysis was performed using PA and liquid cell infrared spectroscopy. The PA
results were inconclusive due to insufficient signal to noise ratio in the region of interest
(approximately 1680 cm -1 to 1720 cm -1 ). It appeared that the number of co-added scans (512 in
this case) at an OPD velocity of 0.5 cm/sec was insufficient. Liquid cell spectra of the extracted
asphalt is shown in figure 2-2.2.17.
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