Trr No. 1323 Materials And Construction, pp. 77-84
The thin film oven test and the rolling thin film oven test are widely used to simulate the asphalt hardening that occurs in hot-mix plants. Using nine road-collected hot-mix samples and the corresponding tank asphalts, a comparison is made between the oven tests and the hot mix. Comparisons are made on the basis of viscosity at 60 centrigate celcius 135 centrigate celcius, penetration at 25 centrigate celcius, infrared analysis, and gel permeation chromatography. In general, the two oven tests are in close agreement for all parameters at standard test times. However, if the times are extended, they may diverge. The recovered hot-mix asphalt is generally more aged than the oven-aged material with respect to all parameters although less so with viscosity. The infrared pectra show much greater change in the hot-mix than in the oven-aged material. The hot-mix operation also procedures highly oxidized material that is not usually removed from the aggregate in the extraction operation.