AASHTO TP 128:17(2019) Standard Method of Test for Evaluation of Oxidation Level of Asphalt Mixtures by a Portable Infrared Spectrometer.
4.1. The test method described is useful as a rapid, nondestructive technique to monitor and detect differences in the oxidation signal of the preproduction laboratory asphalt mixture, its production at the plant, and the newly placed pavement.
4.2. The oxidation values obtained from an asphalt pavement by this test method can be used to determine its aging rate by measuring the pavement oxidation values every six months or at another suitable frequency. Over time, the oxidation values will increase and a pavement aging rate can be obtained.
4.3. The test method is useful to measure the oxidation values for monitoring the consistency of asphalt mixtures containing reclaimed asphalt pavement (RAP).
6. 1. Preparation of Plaii t—Produced Asphalt MLiure Samples:
6.1.1. Collect a representative sample of plant-produced asphalt mixture according to R 97.
6.2.4. Test five specimens using the procedures in Sections 6.2.1 through 6.2.3, with three repetitions each.
6.3. Preparation of Recta ins ed Asphalt Pa vemeis I (RAP) Samples:
6.3.1. If testing the oxidation of reclaimed asphalt pavement (RAP), sample the RAP from stockpiled material in accordance with R 97.
6.3.2. Obtain a sample of approximately 22 kg (10 Ib) of RAP material from the designated RAP stockpile.
6.3.3. Sieve the RAP sample through No. 4 (4.75-mm), No. 8 (2.36-mm). and No. 30 (0.6-mm) sieves.
6.3.4. Use the material retained on the No. 30 (0.6-mm) sieve to fill the stainless steel pipe (Figure 2).
6.3.5. Usc a hammer with the metal tube to compact thc sample to the top level of the stainless steel pipe to obtain a flat surface (Figure 1), and then test with the PIRS device, making sure they are in contact as described in Section 7.
6.3.6. Test five specimens using the procedures in Sections 6.3.2 through 6.3.5, with three repetitions each.
Note I —Section 6.3 is skippcd if the asphalt mixture does not contain RAP.
6.4. hi-Place Pavement Suiflice Measurement:
6.4.1. Randomly select a relatively flat and dry pavement surface area. Brush the surface clear of any material that would prevent contact between the surface and the PIRS device.
6.4.2. The selected pavement area should be marked: take care not to place the PIRS device directly on the marking.
6.4.3. Perform three measurements on the selected pavement area with the PIRS device, as described in Section 7, and away from the wheel path.
6.4.4. Repeat the steps indicated in Sections 6.4.1 through 6.4.3 to test five pavement areas with three repetitions each using the PIRS device.
6.4.5. If an agency sampling plan requires more samples, follow the agency sampling plan.AASHTO TP 128 pdf download.